Diary Of An ADI

A Driving Instructor's Blog

The polling stations open in a few hours.

This is your last chance to use common sense, vote tactically, and keep Boris Johnson and the Tories out of a majority.

You’ll keep seeing morons claiming that a Labour government would bankrupt the country. It wouldn’t. The stark reality, though, is that any government which carries Brexit through will bankrupt the country – sooner or later. Not because of who they are, but simply because of Brexit. Unfortunately, that includes Labour these days.

Johnson is going to have to pay for what he is promising, and since he has already promised the imaginary £350 million a week we allegedly pay to the EU to everyone from hospitals to North Sea fisherman ten times over, the money will have to come from taxes. And since he has already pledged to cut taxes for the super-rich, that means the rest of us – including the idiots who are going to vote for him – will be sucked dry.

Mark my words, here. If Brexit finally happens, it is going to cost us big time. For many, it will cost them for the rest of their lives – even if some of them die happy, knowing that if they had still wanted (or been able) to travel, they’d have been able to use a blue passport.

Your country needs you. Vote tactically.


With only days to go before the General Election, this is your last chance to make a difference.

If the UK goes through with Brexit in any form, we are all going to be screwed. The only people who will be happy will be the crusty old weasels who’ll be clutching blue passports they’ll never use, tears in their eyes, and campaigning that scrod and tripe should only be sold in lbs and ozs.

None of that will do those of us who expect to be around for more than another decade any favours. But that’s all Brexit has going for it. There is nothing else in the bag – a bag that you were told was much bigger than it was to start with.

The number of jobs lost for reasons that are directly attributable to Brexit stood at over 420,000 in late September, The imminent update will likely see it go above half a million. This figure is responsible for £3.6 billion less income and National Insurance receipts, and over £12 billion lost wages. And it will only get worse, because the Brexiters’ only answer is “we’ll be all right because we’re British”.

We won’t be “all right”. We’re not all right now, and we haven’t even left yet. And we haven’t been all right since 24 June 2016,

If we leave the EU, that lost revenue will have to come from somewhere, and that means tax increases. Since Johnson has already promised to rebuild every hospital, and financially support every group whose votes he seeks, and cut taxes for the super-rich, you don’t need to be a genius to work out who is going to end up paying for it. You.

It beggars belief that someone who blusters through every interview with inane comments like “my deal is a super deal and you should all get behind it” and “let’s get Brexit done” – that last one often in answer to completely unrelated questions – might actually be voted into power properly.

Corbyn is no worse, but he’s not much better, either. I still don’t quite understand where the Labour party officially stands on Brexit, even after more than three years. And I’m a lifelong Labour voter and one-time activist. But not right now, while they’re still dithering internally over whether we should Leave or Remain.

For me, my vote is going to the one main party that has openly stated it will stop Brexit. The Lib Dems. I freely admit that I am voting solely on Brexit. I know from experience that no party’s numbers ever add up when the opposition picks them apart during campaigning, and I also know that very few parties deliver everything they promised in their manifestos if they get in. So as far as main policies go, with the main parties there’s not much to worry about. Corbyn won’t bankrupt the country, for example – though Brexit might, and that could bounce back in the future if Labour were to get in.

I’m sure others will vote for Labour for reasons of their own, just as others will vote Tory.

But I hope and pray that the opposition parties – even if it isn’t Lib Dems outright – get enough votes to stop the Conservatives getting back in.

Our futures depend on it.

So think carefully how you vote on Thursday if you’re not one of the nutcases who still thinks Brexit is a good idea, even with all the evidence of the last three and a half years. Vote tactically.


Smearing windscreen in rainI’ve mentioned this in the smearing windscreens article, but we’re approaching that time of year where it gets wet and cold, and a lot of crap gets thrown on to your glass and builds up into a nasty film that doesn’t easily wash off.

I’m always amazed that some people only put water in their wash bottles (if they have anything in at all). I’m even more amazed that some of those using just water are ADIs – and my amazement maxes out when I hear them trying to justify it.

Water on its own does not have sufficient wetting properties to attack oil, wax, and grease. Even proper washer fluid can have problems, which is why you get that mosaic pattern left behind when you wipe in the wet. You need a good detergent to clean off oily deposits, and a small amount of alcohol to assist with wetting. Alcohol also functions as an antifreeze, so whereas using just water means you’re going to get a popsicle with the first frosts, a proper washer fluid will protect you to well below freezing.

A typical concentrated screewash that you dilute yourself is usually used at levels between 10% and 25% in water depending on the weather, and a 5L bottle costs about £5. Depending on whether you’re making a summer or winter mix, every 5L of diluted washer fluid therefore works out at between 50p and £1.25. If you use the concentrate neat – I’ll talk about that later – then obviously a batch costs the full £5.

In a bad winter, with lots of rain and slush, I will easily get through 5L of washer fluid each week. In a dry summer, I might use only a quarter of  that. Over a whole year, I would be paying around £30 for washer fluid if I made it from concentrate. It’s not really a lot of money, but it’s still an overhead.

Of course, you can buy ready-to-use washer fluid, where the dilution has already been done for you. If you find a suitable bargain, you can pick it up for between £2 and £3 for 5L, but the normal retail price is similar to that of a bottle of concentrate. It means that you’re paying between £1.50 and £5 extra for what you can essentially get out of a tap! A lot of people buy this ready-to-use stuff, but if I were to do so, it could cost me between £75 and £170 a year depending on how much I’d paid for it.

Also remember that retailers are sneaky and they put prices up in winter. At one time, for example, my local Makro was doing BOGOF on the concentrate I used to use – and it was a good price to start with. But they only did it during the summer when demand was low, and in winter the price doubled and there was no BOGOF. If you buy it, stock up when it’s cheap.

So, is it possible to make your own screen wash cheaper than this? Washer fluid needs to be able to do two things:

  • clean
  • not to freeze when it gets cold

It’s basically just a mixture of alcohol and water with a bit of detergent.

Alcohol – as ethanol – functions as an antifreeze and a wetting agent. The whole subject of freezing point depression in alcohol/water mixtures is a huge topic in physical chemistry, but the bottom line is that pure water freezes at 0°C, whereas adding different amounts of alcohol lowers the freezing point. A 10% ethanol/water mixture freezes at -4°C, a 20% mixture freezes at -9°C, and a 30% mixture freezes at -15°C. A typical commercial concentrate (£5 for 5L) which claims it freezes at -6°C when used neat must therefore contain 15% alcohol.

Alcohol is the most expensive ingredient in screenwash, and a 15% solution will have 750mls of ethanol in a 5L bottle of concentrate. Ethanol can be purchased for around £2 per litre, so a 15% concentrate will contain about £1.50 worth.

Whatever detergent you use has to be relatively non-foaming – you don’t want bubbles blowing down the street when you use it – and it has to be the kind that is actually going to attack the crud that get on your windscreen. This is another big chemistry subject, but to cut a long story short, Traffic Film Remover (TFR) is ideal. TFR gets anything off your car – tar, oil, mud, insects, bird crap, dead squirrels, that sort of thing. I get mine from JennyChem, and it costs £12.50 for 5L. However, you only need to use it at a concentration of between 1% and 2%, so 5L will go a long way – you need about 15p to 30p worth of TFR in your DIY concentrate. One 5L bottle of TFR will make up to 70 batches.

A batch of DIY concentrate will therefore cost around £1.70 versus £5 for commercial brands. Each batch of diluted washer fluid will cost you between 17p and 45p.

What if the temperature goes below -6°C?

When we had those two cold winters some years back, the first one caught me out, and my washer fluid froze – even though I’d followed the directions on the concentrate bottle. I’m a chemist, so the solution was simple: I nipped into a hardware store and bought a small bottle of methylated spirit, and poured that in. After half an hour or so, my wash bottle was defrosted. That was when I got the idea of making my own washer fluid – I would always know what temperature it was good down to.

So, the answer is to increase the amount of alcohol in your mix. Even using your DIY mix neat is going to be a lot cheaper than buying a low-temperature version – the price is proportional to the amount of alcohol in them. But for even lower temperatures, increase the alcohol to 20% or 25% in the concentrate and use it neat. It’s still cheaper than buying it.

How can I prepare for cold temperatures?

You just have to use common sense. In summer, using concentrated screenwash neat is just a waste of money, so it makes sense to use it at the 10% dilution (negligible antifreeze properties). When it gets colder, a 25% dilution will be good to about -2°C. If it gets very cold, use the “concentrate” neat to protect down to -6°C. If it gets really cold – below -8°C or so – add extra ethanol to the neat concentrate. An extra 500mls (£1 worth) will protect down to about -12°C.

Can I make it with more alcohol in it?

Yes, but be careful. Ethanol is flammable, and on its own has a flash point of 14°C (that means that at that temperature and above, a combustible vapour exists that can easily be ignited). A 10% solution in water has a flash point of 49°C, which is much safer. A 20% solution has a flash point of 36°C, which is still safe unless you store it in a very hot place. A 30% solution has a flash point of 29°C, and this is quite likely to be encountered in hot weather. My advice is not to exceed about 25% of ethanol.

If you make up the DIY concentrate using 1L of ethanol instead of 750mls, it’ll be good down to  -9°C. In fact, I am fairly certain that the brand I used to use was once safe down to that temperature, but somewhere between 2010 and the present it started referring to -6°C as the lower limit. I suspect they reformulated to cut costs, and dropped the alcohol content from 20% to 15%.

Don’t store a strong winter mix in your car during the summer. And definitely don’t carry any neat ethanol during the summer months, and only the smallest amount in winter in case you have to do an emergency defrost like I did that one time.

It seems complicated making your own

That’s why there is a market for ready-to-use screenwash. It’s up to you.

What kind of water do you use?

Tap water will work for most people. It’s probably what they use when they’re diluting commercial concentrate. However, tap water contains dissolved minerals – especially in hard water areas – and it leaves white streaks when it dries. It’s best if you use distilled or deionised water. Distilled/deionised water doesn’t do that. The only problem is that unless you already have access to it – and you might – buying such water is relatively expensive (50p per litre), and would add £2 to the cost of your DIY concentrate.

Personally, I used either rainwater (boiled) or the condensate from a dehumidifier we have to inhibit condensation and mould growth. If you store this source of water, make sure you store it with the alcohol already added, as that inhibits the growth of algae.

I just use water

Water on its own is no good. If the temperature falls, it WILL freeze. Even if it doesn’t freeze in your main washer bottle, it will in the pipes and at the nozzles. Water alone also doesn’t clean many things off the glass – it won’t touch oil, grease, or squashed insects, and it will struggle with tree sap.

If you do get a freeze up, trying to use the pump might cause it to burn out. Although I haven’t come across the problem recently, it can also cause pipes to burst or become detached from the main storage reservoir in your car (many years ago, that was a regular occurrence on a Citroen Xantia I used to have).

And remember that if you are driving without the ability to keep your windscreen clear, you are committing an offence. The Road Vehicles (Construction and Use) Regulations 1986 says:

Every wiper and washer fitted in accordance with this regulation shall at all times while a vehicle is being used on a road be maintained in efficient working order and be properly adjusted.

Arguably, you are not complying with this if you just use water. If it freezes (or the bottle is empty) and you drive, you’re definitely not complying with it. It is shocking that some ADIs are apparently doing this.


This is an older article. It has been updated several times to maintain the link to an up to date DL25. However, note that since November 2019, DVSA has switched to using an electronic version of the DL25 via iPads during the test. There is no longer a paper record created during the test.

What happens is that the candidate is told whether they passed or failed, a debrief is given the same way it always has been (referring to the faults displayed on the iPad), and a copy of this same results list is emailed to the address given when the test was booked.

It’s a straightforward exercise getting the pupil to email or text you a copy if you really need it. Quite frankly, in most cases you don’t – you can refer to the pupil’s copy the next time you see them, and you’ll already be aware of what they failed for by listening to the debrief.

For the time being, the original DL25 is still available for you to print off, and using these on your lessons is still perfectly valid. I have a laminated one I refer to.

This link (click the image) points to the official PDF DownloadDVSA DL25 form. All pages of the DL25 are included in the file.

A blank DL25 consists of a front marking sheet (DL25A) and two carbonless copy pages (DL25B and DL25C) underneath. There is an explanatory sheet (DL25D) at the back.

The examiner gives the candidate the back two sheets (DL25C and DL25D) at the end of their test, whether they pass or fail. They also get a Pass Certificate if they pass the test.

DL25B has a back side, which the examiner completes back at the test centre. I haven’t a clue (or any concern about) what happens with DL25A and DL25B within the DVSA once the test is closed.

DL25C (the candidate copy) also has a back side, detailing the appeals and complaints procedure. DL25D is also double-sided.

The PDF file contains all sides of the relevant pages.

The test report is explained in detail in this article.

Can instructors use an iPad when doing mock tests?

The short – and correct – answer is no, they cannot. There’s no point arguing about it: you can’t.

When a candidate is on their test, they are not classed as a learner driver. Therefore, the examiner is not the supervising driver. That is why the examiner is not breaking the Law by filling in an iPad form.

However, when they are on lessons, pupils are still learners, and that means the instructor is the supervising driver. It is illegal for whoever is in overall control of the car to use a handheld device while the car is moving (or if the engine is on, even if you’re stationary, if you’re going by the letter of the Law),

Personally, I have never understood the fascination many ADIs have with “mock tests”. The only test that matters is the real one – because it is conducted by someone who is specifically trained and authorised to administer them. Anything else is just play-acting. This is even more true when the test conductor insists on dressing up in hi-vis jackets and farting about with a clip board, when they’re either going to mark more harshly than an examiner would, or more leniently simply because they’re not examiners and can’t mark properly. While staging this performance, they are still the supervising driver.

Having seen paperless tests in action, I can assure you that filling in a DL25 by hand is not going to ruin the impression you give during your mock test pantomimes.


Fogged up windowsThis is an old article from 2013, but it is due an update. When I originally published it, one of the show-me-tell-me questions was:

Show me how you would set the demister controls to clear all the windows effectively. This should include both the front and rear screens.

At the time of updating, the relevant show & tell questions (they changed the name) are:

When it’s safe to do so, can you show me how you’d set the rear demister?

When it’s safe to do so, can you show me how you’d demist the front windscreen?

For the windscreen – that’s the one on the front of the car – the universally correct answer would be that you’d switch the airflow to blow out of the vents on the rear of the dashboard up at the windscreen, turn up the fan speed, and increase the temperature of the air from these vents. That would work for any car, although the actual knobs to twist and buttons to press will vary from model to model.

For the rear window, you’d turn on the electric heater that warms those little metal wires stuck to, or embedded in, the glass. There will be a button somewhere on the dashboard that turns it on and off.

You will note that the original broad question has now been changed to two rather more specific ones. This is relevant, because most newer cars also have air conditioning, electrically heated front windows, and often a button labelled as “MAX”, which turns everything on to demist all the windows very quickly at the same time. One press and you turn on the front and rear window electric heaters, the air conditioning, and redirect the hottest air possible at the windscreen (and often the side windows, as well, if your car has that feature).

When asked the original show-me-tell-me question, operating the MAX button was a perfectly correct response – as were playing around with the air flow controls, using the heated front windscreen if you had one, and turning on the rear window heater. However, with the much more specific Tell questions currently used, pushing the MAX button isn’t strictly the right response to either of them. It is also worth noting that whereas the original question would have been asked whilst stationary, if either of these new ones are asked, it will be while the candidate is driving. Ever since they started doing it this way, I’ve had nightmares about people fiddling with buttons and dials while taking a bend and losing control (I know the examiner would prevent that, but at the very least it would result in a test fail).

Arguably, operating the MAX button is a satisfactory response to either question, because it will achieve the desired result. But it is technically not the correct response if you’re being pedantic about it, because it does several other things at the same time.

It makes sense to understand all the controls rather than just blindly push buttons and twist knobs. If nothing else, if you inadvertently turn the car into a sauna, you ought to know how to turn the temperature back down again – and you’d be surprised by how many people can’t work out for themselves that if you turn something on by pressing a button or flicking a switch, you can usually turn it off by pressing the button again, or flicking the switch the other way. It also means that if you respond to the examiner’s question by pressing the MAX button, you’ll probably be able to recover if he specifically asks you to demist either the front or back – but not both.

How does the air-blower demist windows?

It involves a bit of science, but it is enough to know that hot air will demist windows, whereas cooler air probably won’t.

The reason it works is down to relative humidity. Air can hold water vapour as a gas, but if the amount of vapour reaches the maximum that the air can hold, it precipitates out – condenses – as water droplets. That’s the “mist” on the glass. The problem is that the maximum amount of vapour the air can hold before condensation occurs gets less and less the colder the air is. If you refer to water vapour in air as the “humidity”, then the amount of vapor relative to the maximum possible is the “relative humidity”. In summer, a relative humidity (RH) of 70% might feel horribly sticky and sweaty – but there’d be no condensation. In winter, you can easily get 100% without feeling it because there’s a lot less moisture there– but since there’s no room for any more vapour in the air, any extra causes condensation to take place. Think of it as a bucket overflowing, where the colder it is, the smaller the bucket is.

What happens is that on cold mornings, with the air at – or very closer to – 100% RH, as soon as you get in the car, breathing and perspiring, you overflow the bucket and condensation takes place. You see it on the glass as mist, but everywhere feels slightly damp. When you initially turn on the heater, it is blowing cold air, and if anything you get even more misting. But as the car warms up, it starts to blow warmer air. This warm air can hold more water vapour, and it evaporates the mist as it blows across it and keeps hold of it.

What does the air conditioning do?

Air conditioning (A/C) units pass the air over a radiator filled with coolant – just like what you have in your fridge at home. If you look back at what I said about humidity, above, you can probably work out that if you cool very moist air, you send it above 100% RH. The excess moisture – and if you cool humid air at 30°C down to 8°C, there’ll be a lot of it – condenses out (usually as a pool of water under your car in summer if you’re stopped), and much cooler and drier air is blown into the car. You can play around with the temperature of the air that is blown in by passing it over the heater radiator, so you have crude climate control.

Since it removes moisture, A/C is extremely efficient at demisting and preventing further misting.

How do the heated windows work?

In a similar way to the air blower. As they heat up they create an area around the metal wires which is warmer and so the mist evaporates back into the air. They work best in conjunction with the car heater, which heats the bulk of the air in the car, and which can then keep hold of the vapour, preventing condensation. They work even better with the A/C, because it strips the vapour out and dumps it outside the car. The MAX switch activates everything in one go.

How do you control these features?

It varies from car to car, but for the heater blower, there will be several rotary controls usually located in the centre of the dashboard and below the level of the steering wheel.

Heater controls

One of them controls the speed (and noise) of the fan, one controls the temperature (blue is cool, red is warmer), and another allows you to select which vents and grilles the air will be blown through (at your feet, at your face, at both, or at the windscreen – possibly with other combinations).

Higher spec cars may have digital temperature displays, and some will have independent control for each side of the car. Some will even have controls in the rear for back seat passengers.

Heated Front Window Symbol

Heated Rear Window SymbolThe heated rear window button will have an icon like the one on the left, and the heated front windscreen will have one like that shown to the right.

The air conditioning will be activated with a button or switch marked A/C, and the MAX button (which activates all of these features) may also have one of the window icons.

Isn’t the heated windscreen for de-icing?

Not specifically, no. It serves the exact same purpose as the heated rear window – to demist. However, every demisting feature in the car can also de-ice if necessary. Even blowing cold air can lead to de-icing if it isn’t too cold, because the air passing through even a cold car is still warmer than that outside. However, a heated front window is noticeably useful at de-icing since that’s the very window that needs de-icing the most.

Having said that, a heated windscreen is only good at melting frost or dislodging a thin layer of rimed ice. If you think it’s going to get rid of a couple of inches of snow, think again. It doesn’t actually get that hot – if it did, it could cause the glass to shatter.

Why do my windows steam up in summer if it’s been raining?

That’s because water cools as it evaporates. If it’s already humid when it rains, the air passing over the windscreen evaporates the rain drops, so you get cooling around them. The humid air inside the car is then above 100% RH close to these spots on the windscreen, and condensation occurs. You usually see it around spots of rain.

You can also get it if you’ve had the A/C on. It cools the windscreen right down, so when you turn the A/C off and humid air gets back in, the cold zone near the glass sends the RH there above 100% and condensation occurs. In this case, misting is more uniform, but often concentrated on the lower part of the windscreen where the A/C has been blowing.

So what should I tell the examiner on my test?

Your best bet is to answer the question he’s asking you. If he asks how you demist the back window, operate the heated rear window switch or button. If he asks how to demist the front, either demonstrate how to redirect the air flow and increase the temperature and fan speed, or operate the heated windscreen button or switch (if your car has it).

In Nottingham, examiners have not been querying use of the MAX button, so use it by all means – but just make sure you know how to activate just one of the features as necessary if your examiner presses you on the subject. You are being tested on “safe driving for life”, so you ought to know what the buttons do anyway – you’re going to need to if you pass.

Since these questions are asked while you’re driving (and since you’ll be driving when you use them once you pass), be careful not to stare down and lose control of the car.


Ford Focus One-Touch Window ButtonsMy Focus has one-touch electric windows. On my last car, shortly before it was due for a service, the driver-side window developed a fault whereby when it was closed and hit the top of the frame, it bounced half way back down. What I had to do was carefully inch it up and make sure it didn’t hit the top each night when I got home and locked it up. There was still a small gap, though, but it had a service booked and we had no rain, so it wasn’t an issue.

The dealer fixed it and simply said it had been “reset”. I had no further problems with it.

I have another car now, and it has started doing the same thing. It isn’t anywhere near ready for a service yet, so in order to avoid the inevitable assessment visit and probable brake bleed my dealer would insist on before fixing it under warranty, I looked into it a little further. And big surprise, it is quite common on Fords (and other makes, apparently).

From what I can gather, the reset procedure is to put the window all the way up holding the button, and then keep it held for 3 seconds. Then, push the button and put the window all the way down, then keep it held for another 3 seconds.

But that doesn’t work by itself, because as soon as the window hits the top of the frame, down it comes again. It seems to be connected with the safety feature that prevents idiot kids (and dogs) getting their heads squashed if the window goes up while they’re leaning out. A sensor detects the resistance and winds the window back down again.

The trick is to use a piece of paper or thin card when you do the reset. Hold it just under the top window frame recess and put the window up. Hold the button for 3 seconds. The paper acts as a cushion and prevents the sensor triggering. Now put the window down and hold the button for 3 seconds. That should now have reset the sensor and the window goes up and stays up.

It ought to go without saying – but I’d better say it anyway – do not use anything hard as your cushion, otherwise you’re likely to break the glass. Use paper, and fold it once or twice as necessary to get enough cushioning to stop the auto-retraction kicking in while you do the reset. And keep your bloody fingers out of the way when you’re doing it. Don’t say I didn’t warn you!

My windows bounce back when they reach the top

You may have a faulty motor or sensor, but from my experience it is most likely just needs a reset. Follow the instructions above. That should reset it.

My windows come down on their own

I have read that on some models there is a feature which automatically opens the windows when it gets hot – even when it is unattended, and sometimes in the middle of the night. I have also read that the windows in some cars can be controlled from the key fob, and this can get pressed whilst in someone’s pocket. The sources for this are various web forums, and are not really to be trusted, but even if such a feature existed, I can’t believe that would be available in the UK because the car would get stolen almost immediately in some areas.

It is possible you need to do the sensor reset without knowing it, and the windows actually opened before you locked it up but you didn’t notice. That’s just a thought, and I’m not saying it’s right. But the first time I experienced the bounce back I didn’t realise until I went out again and saw the window open.

If I woke up to open windows, I’d book it into my dealer pronto.


PostboxOver the last few weeks there have been reports that Royal Mail  staff are threatening to go on strike over Christmas. There is one burning question in my mind on this if they do strike.

How would anyone bloody know?

Back in September, I purchased something from a seller on Amazon. It wasn’t fulfilled directly by Amazon, and the seller sent me emails with a delivery window. When the item didn’t arrive, they quickly sent me another, which arrived promptly. I told them I’d let them know if the first package arrived, but it never did.

We’re now well into November, and last week I got a card through my door telling me the Royal Mail had a delivery for me, but that it needed outstanding postage paying on it before they’d bring it. I had several parcels expected, so I paid the outstanding amount – a couple of quid – and waited to see who it was who’d messed up so I could claim it back from them (when you order through PayPal and Amazon, you have no worries on that score).

The delivery date Royal Mail had given me was a day last week, but by the day before that all the stuff I’d been expecting had arrived, and there was no indication or reference number that suggested any of those were involved. I was wondering what the hell it could be – I’d forgotten about the lost September delivery.

Come Saturday – and you can probably guess what’s coming – the September package was delivered! It was clearly dated September, but it had taken them until November to action it. A total of 50 days. I informed the Amazon seller, and they kindly told me to keep the second item as a goodwill gesture (so I got a spare of something I will almost certainly buy again at some point for a couple of quid when it normally costs ten times more).

But that’s not the point. The Royal Mail is likely to be hit by strikes for more pay by the arseholes responsible for things like this.

Items go missing on a fairly regular basis for me – I can count on a few a year for sure – and when I contact sellers it is always Royal Mail deliveries involved, and never couriers. You can be sure that I make my views on the Royal Mail well known at that point. What really bugs me, though, is the thought that at this time of year they take on a lot of temporary staff, many of whom couldn’t get jobs anywhere else, and with the occasional stories in the press where individuals have been either stealing or binning the post instead of delivering it… well, you have to wonder.

Then there was that time they suspended all deliveries on my road for a fortnight because a dog inside a house had barked at a postman (we’d assumed he’d been mauled and lost an arm or something until we spoke with the owner). The whole bloody street. We had to collect our mail from the sorting office. And what was funny was that the majority of the houses in the exclusion zone were further away from the one with the dog than all the ones round the back. It wouldn’t have surprised me to discover they’d also forbidden staff to even drive down the road.


Li-ion generic batteryI’ve had a Nextbase 612GW for over a year now. It records in 4k – meaning that you can see number plates and other details much further away and much more clearly than on other dashcams.

I’m actually on my second unit. Within a year, my first one stopped turning on automatically, and after discussions with Nextbase, they gave me an authorisation code so that Amazon would accept the return and refund me. I bought another in lieu of the refund.

What had happened was that the internal battery had died. It would barely run for 30 seconds after a four hour recharge, and since it is the battery that provides the camera with enough residual power to detect when the power systems in the car are activated (which tells it to turn on and start recording), it was kaput. It worked perfectly if I powered it on manually each morning once a bit of charge had gone to the battery, but any power down lasting more than an hour and the battery would drain again.

Any 4k video device right now gets warm when it is in use, and the 612GW is no exception. I wouldn’t say it gets hot, but certainly very warm, and with the summer we had in 2018, it got warmer still. Li-ion and Li-Po batteries are degraded by high temperatures, and I suspect that overall this contributed to the battery going as quickly as it did. OK, it may also have been a bad batch (or just a bad one in my case), but I didn’t go into that with Nextbase. I’d had it replaced, after all.

It is worth noting that Nextbase told me replacing the battery is quite easy, and they supply them if you ask. It does involve a bit of soldering, but I will bear it in mind for the future.

As I understand it, some cheaper dashcams use a capacitor to hold residual power. However, where a battery is involved, this problem of degradation could occur with any model of camera. Indeed, any battery-based dashcam will effectively “break” sooner or later once the battery dies. Exactly the same thing happens with laptops, phones, and tablets – and it is amazing how many people don’t realise it’s just a dud battery which, in many cases, could easily be replaced. It even used to happen with desktop computers, when the coin battery which held the BIOS settings that enabled the PC to boot died (I’ve replaced a fair few of those in the past for people who thought their PC was broken).

I suspect that a lot of the complaints you see about dashcams dying could be a result of this – along with using the wrong types of SD card.


Apologies to anyone who has followed the Jennychem links and been met with a 404 error. They updated their website, and it wasn’t until I came to place a new order that I realised. The links are fixed now.

The problem of smeared windscreens in the rain has driven me nuts ever since I started driving, but it became a major headache when I became a driving instructor.Smearing windscreen in rain

We’ve all experienced it. You get a few spots of rain, and when the wipers wipe you get a mosaic pattern left behind for a few seconds. In heavy rain it’s like someone poured chip fat on the screen and you just can’t see properly. I’ve had varying levels of success removing it – scrunched up newspaper (no good), sodium lauryl sulphate (not bad), various solvents (fair), Clearalex (quite good) – but things came to a head when my lease company replaced my car a few years ago. In rain you couldn’t see anything, and absolutely nothing would get rid of whatever it was on the windscreen. I was so bad, I seriously thought that the glass must have been damaged in some way.

Essentially, what causes it is oil, or something related to oil (grease, wax, and so on). Virtually every vehicle on the road leaves deposits behind. Some of it is dusty, some is gritty – but a lot of it is oily or greasy. That’s why when it rains after a period of dry weather we’re advised to take care, because the road can be very slippery as oil sits on top of the wet tarmac before being eventually washed away. Obviously, any road spray is also going to be mixture of dirt, oil, and water, and when this gets on to your windscreen you start to get smears. Now, up to a point, your screen wash can deal with it, but eventually the oil seems to bond to the screen such that removing it is no longer easy.

Strangely, washing your car can also lead to the same sort of problem – especially if you use a car wash (hand or automatic). Any wax on the rags or brushes will transfer to your windscreen, and if you’ve ever noticed how a single greasy fingerprint is capable of smearing across the whole windscreen (unless you use something that lifts it off), it doesn’t need much to cause smearing on the outside when the glass gets wet. It also gets on to the rubber of your wipers, and collects underneath them when they’re off, so even if you manage to clean the glass the wax is smeared back again from the rubber as it dips into the stuff in the gutter, just like a pen dipped in ink.

The particular problem with my lease car this time around turned out to be, as far as I can tell, the result of a manufacturing residue. Something gets on the glass during manufacture, and it’s still there when you get hold of the car.

How can you get it off?

Most detergents and surfactants will remove the normal deposits of wax and oil with varying degrees of success, though car wax is particularly stubborn. Even Fairy Liquid works up to a point. Some cleaners are more powerful – for reasons of chemistry – and are much more effective. Clearalex can be purchased (these days it’s a liquid, but you used to be able to buy it in sachets in powder form), and you add it to your screenwash. The problem with it is that it leaves a horrible white residue when it dries. I have had some success with Sodium Lauryl Sulphate (SLS), which is an anionic surfactant used in many household products. It removes quite a lot of windscreen gunk, but it didn’t seem to touch wax (it also leaves a slight residue at the concentration you have to use it at).

Then I came across sugar soap. I’d not heard about this before, but it is used by decorators and builders to remove grease and dirt from surfaces prior to painting. Sugar Soap - from Screwfix

Wikipedia describes it thus:

Sugar soap as typically found in Commonwealth countries is a cleaning material of variable composition sold for use on surfaces affected by greasy or tarry deposits which are not easily removed with routine domestic cleaning materials. When in dry powder form it looks like table sugar thus causing the name.

The solution is alkaline and its uses include cleaning paintwork in preparation for repainting.

It looks exactly like Clearalex powder, and I suspect that there may be some similarities in chemical composition. However, compared to Clearalex, sugar soap is dirt cheap – one 5g sachet of Clearalex costs about £1.50, but sugar soap is about £2 for nearly half a kilo from Screwfix. I bought some and made up a batch. I soaked some soft cloths in it, gave the windscreen a good scrub and rinse, then took the car out for a run in the rain.

Initially, I thought it hadn’t worked, but with each wiper pass the glass was getting noticeably clearer. The sugar soap appeared to have softened whatever it was on the glass and it was gradually coming off. So when I got back home I made up another batch and soaked some rags in it, then left them covering the windscreen (including the bit at the bottom) for about half an hour. I also cleaned the blades with it. This time the windscreen was absolutely crystal clear.

Sugar soap is great for one-off cleaning, and it got rid of the residue I’d had trouble with, but it leaves the same horrible residue if you put it in your screenwash for normal use.

Not long after this I stopped using my local ESSO garage because the new management had added 5p to their fuel prices (they used to match Asda, but overnight became one of the most expensive in Nottingham). I shifted from using their Tiger Wash machine to a hand car wash, and I was intrigued at how clean they could get the car just using some small garden hand pumps and a power spray. The next time I was in, I did a bit of snooping around the bulk containers of the concentrates they were using, and discovered “TFR” – which is “traffic film remover”.

After reading up on this, I bought some TFR from a company called JennyChem. They also supply the mysterious cherry-smelling shampoo the hand car washes use. In a nutshell, a 1-2% TFR solution gets all the oil/wax film off a windscreen in one go, and it also seems to also attack the residue I’d been plagued with on my lease cars since that first one that had it, though sugar soap is still best for this. The same concentration in your wash bottle keeps it off, and it doesn’t leave much residue.

As time has gone by, I have started using the TFR in a small spray bottle to clean my alloys and bodywork in between visits to the hand car wash when I have an upcoming test. It removes brake dust from alloys like all get out, as well as summer tree gum and bird crap (especially when the little sods have been eating blackberries and insist on sitting on the telephone wire right above my driveway).

As a footnote, my hand car wash has just started using what I am assuming is a liquid wax (I haven’t yet identified it) that makes water bead very easily (and very impressively) when it rains. The problem is that it gets on the windscreen, and it is a sod to get off (two sugar soap treatments did it).

And a final note. You can make your own screenwash using TFR.

Does TFR damage the windscreen?


Does TFR damage paintwork?

If it is the non-caustic type, and if it is used at the manufacturer’s recommended concentration, no. But remember that TFR will remove any wax you have applied, so you will need to re-wax after using it on painted surfaces. However, removing wax is exactly what you want if it’s on your windows.

Strongly caustic types – which are cheaper and harsher, and often used to shift several centimetres of crap off the undersides of lorries – could damage painted surfaces if used at high strengths and if left on for too long.

The stuff supplied by JennyChem (linked to earlier) is not strongly caustic as far as I am aware, and is specifically designed for use on cars.

Does TFR leave a residue?

The stuff I use doesn’t – well, no more than normal windscreen washer solution does. You’ve got to remember that when you use your windscreen washers, you’re doing it to remove dirt on the windscreen. That dirt is visible, so when you wash it off it will leave visible streaks outside the wiper area when it dries. It’s like when a bird drops a load on the screen – when you wipe it off there’s a good chance it will sit on the screen at the edge until you scrape it off by hand. There’s not much you can do about that.

Is there a non-chemical solution?

A reader (from Australia) wrote to me to tell me that he had had success removing that new-windscreen film using Cerium Oxide paste. You can buy it easily from various places (including Amazon) in various forms – powder, paste, or block – and it is specifically used for polishing glass. If you buy it, make sure you get the finest grade possible – ideally, one which is specifically sold for the intended purpose.

Can you put oil on the windscreen to prevent smearing?

Or, as it was put to find the blog, “can u put oil on wind screen 2 prfent rain”? NO. It will make it worse. It’s oil (and suchlike) you are trying to remove. Put it on deliberately and you could end up killing yourself – you won’t be able to see properly.

You can buy things like Rain-X, which are intended to make water bead up and roll off more easily, but those who use it often complain that it is patchy in coverage and leads to worse problems with smearing when the wipers pass over the glass, especially as it starts to wear off. I nearly tried this, once, but the risk of it causing more problems put me off. I’m not saying it doesn’t work, just that not all reports about it are as positive as the advertising is.

My windscreen is smearing when it snows

That’s probably a different thing, and not “smearing” at all.

When the windscreen wiper rubbers get cold, they also get stiff. As a result, instead of flexing to the windscreen contours and bending forwards an backwards on each stroke of the wiper, they snag and bounce across. They may even not touch parts of the screen properly on the wipe. All of this is often accompanied by a horrible grunting sound, and it leaves behind a trail of smeared water.

Also, if there are remnants of snow on the blades, this can leave a trail of melt water as the blades wipe.

There’s not much you can do if it’s really cold except put up with it, or let them warm up as the windscreen warms up (a cold windscreen will also smear until it warms up). But scrape off any snow or ice and at least you won’t get melt water (and they’ll warm up quicker if they’re going to).

I see rain spots after my wipers wipe

You’ve got wax or some other coating on your screen. I get it after I’ve been to the car wash, and I get it off using TFR and/or sugar soap. I would guess that you also have a visible line where the wipers stop at the end of their wipe span – that’s where they pull wax or oil residues from the bottom of the screen and leave it behind as they change direction. Like I say, TFR gets it off.

Don’t forget that the wiper blades must also be cleaned. There’s no point cleaning the glass of wax if the rubber still has it on it. The wipers will put the wax back as soon as you use them.


They’re at it again. Someone has asked for advice on car leasing, and one of the replies (answering the wrong question, anyway) has stated that someone on a franchise pays £1,000 a month, whereas if you buy your own car and go independent, you save £1,000 a month.

How many more bloody times? NO. YOU. DON’T!

However you obtain your car, you have an ongoing cost associated with it. Unless you’re driving a 15 year old banger that never goes wrong, needs no maintenance or servicing, never has anything wear out or get a nail in it, and doesn’t need insurance, you are probably paying at least £250 a month for it all told. If it’s less than about 8 years old, this overhead cost could easily be £400-£500.

It isn’t just about how much you are paying for it per month if it’s on hire purchase. Or how much you initially paid. You have to factor in depreciation and having to replace it periodically, any maintenance, insuring it (lots of complaints about insurance hikes lately), getting dual controls fitted/removed, repairs, and so on. It isn’t costing you “nothing”. It’s costing a lot more than nothing.

Even if there is someone out there who has a banger, and does all their own servicing and repairs, they still have to get hold of parts and consumables. The equipment they use to do the work has got to be paid for somehow. And so does the time it would take them to do it – how on earth can you be a full time ADI if you are also a part time mechanic?

There is absolutely no such thing as an instructor car that “costs nothing”. But there are a hell of a lot of ADIs who don’t understand this.

I’ve explained it before in the article Should I Become A Driving Instructor?

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