De-icing with warm water - CGNorwich

Following comments of a number of people on this site I have foregone the scraping and spraying and taken to pouring a bucket of warm water over the screen with excellent results. A number of people have warned me however of the likelihood of cracking the screen, although nobody knows anybody to whom this has actually happened. Has anyone any experience of this ever happening?
De-icing with warm water - piston power
Yes i do this start off with luke warm first then to warm/hotter but only tap hot not kettle hot.!

Never had a problem but saying that a hot kettle might crack it i would not like to find out.!! lol....
De-icing with warm water - rtj70
I used warm water this morning... it then froze ;-) but it was still -4 deg C outside. At times like this I miss the Ford heated windscreen.
De-icing with warm water - Jcoventry
I used warm water this morning... it then froze ;-) but it was still -4
deg C outside. At times like this I miss the Ford heated windscreen.


Yeah but then you have the door windows to deal with...they're not heated!
De-icing with warm water - tyro
I've heard the same warning for years, but never heard of the worst happening. I'm pretty sure that the windscreen is safe unless you use water that is very hot.
De-icing with warm water - Stuartli
The water used should be tepid - I've used the method over many, many years but, fortunately, our drive has a modest slope and most of the water runs away afterwards.

I would think twice otherwise because of the fact that the water runoff could well prove an even greater hazard if it continued to freeze.
De-icing with warm water - CGNorwich


Have only used warm water, not hot. Pretty sure that cracked screens are a myth.
De-icing with warm water - TheOilBurner
I think I've probably de-iced the windscreen with lukewarm water maybe a 100 times. Never cracked a screen yet.

What I do find is that I need to get the wipers going ASAP to stop the screen re-freezing.

I use 2 jugs of water initially, followed by 1-2 more as required.

It's not foolproof, and I have soaked my leg and foot a few times but I just hate scraping the car with a bit of plastic. The scraper can be a bit hopeless when it's been *really* cold too, IMO, but I keep one in the car for one I'm out and about and the car freezes, and then I remember why I normally use warm water!
De-icing with warm water - Alby Back
German bloke next door is something important at Bentley. He's used to cold weather being...well....german.... and presumably knows a thing or two about cars as too. Anyway, he simply chucks boiling water from his kettle over his windows and drives off in a morning. I couldn't bring myself to do it though....
De-icing with warm water - Number_Cruncher
My screen has a crack in it on the passenger side from stone damage. Pouring water over it to de-ice hasn't made the crack grow. It's *much* easier to make an exisitng crack grow a bit than make a new crack initiate.

The co-efficient of thermal expansion of glass is very low, and it isn't a great conductor of heat, so, the area where you pour the water onto is likely to be in slight compressive stress rather than tensile [there will be surrounding glass put into some tension for equilibrium, but this is distributed over a larger volume of glass, and so, the stresses are, therefore, lower]. Generally, cracks don't grow under the action of compressive stress - if the car has a toughened screen, there's already a built-in compressive stress at the surface of the glass, making crack growth even less likely.
De-icing with warm water - Old Navy
If a heated screen switched on at minus umpteen C doesn't crack a screen I doubt if warm (note warm) water will.
De-icing with warm water - CGNorwich
"If a heated screen switched on at minus umpteen C doesn't crack a screen I doubt if warm (note warm) water will."

That's a good point. The only thing I miss from my CMAX is the heated screen
De-icing with warm water - old crocks
I have never heard of anyone having a problem.
I used to use kettle hot water 30 odd years ago but wouldn't now just in case I've run out of luck and fall foul of the "I told you so" brigade.
De-icing with warm water - bathtub tom
An advert currently running on the telly indicates the car heater could be enough to open up existing screen damage, as well as potholes.

If you believe everything you see on the telly. ;>)
De-icing with warm water - Number_Cruncher
An advert currently running on the telly indicates the car heater could be enough to
open up existing screen damage as well as potholes.



Yes, owing to the poor heat conduction properties of glass, heat on the inside will give tension on the outside surface which can cause existing cracks on the outside surface to propagate.

De-icing with warm water - J Bonington Jagworth
"heat on the inside will give tension on the outside surface which can cause existing cracks on the outside surface to propagate"

I hesitate to contradict you NC, but unless by 'outside surface' you mean that adjacent to the vinyl layer in the middle (which provides both a mechanical and a thermal break), then what happens to either layer of glass will have a limited effect on the other. I assume you're talking about a laminated front screen, of course!

FWIW, I've used hot water to de-ice car glass for nearly 40 years, and have yet to crack one. The extra warmth also serves to prevent internal misting until the heater starts to work.
De-icing with warm water - Number_Cruncher
Yes, I was thinking more about a toughened screen rather than a laminated one.

The laminate layer will have a coefficient of expansion which is orders of magnitude larger than the glass, and, in particular, being a thin layer, it can transmit shear stresses effectively. As for thermal properties, I would imagine the laminate conducts heat much more effectively than the glass!

The laminate does act as a crack arresting mechanism, it has a very high fracture toughness, while the glass has only a very low one (typically 1 MPa m^(0.5).

The broad mechanism I'm describing is that for glass to break without an obvious impact or trauma being the cause, you need two things to happen together, a defect or crack AND tensile stress opening that crack.

You are much more likely to find significant defects on the outer surface, which means that the outer surface is much more sensitive to tensile stress than the inner, which is why the thermal gradient going from hot outside to cold inside is, generally, safer than the reverse.

Owing to the low fracture toughness of glass, for typical engineering stresses, the critical crack size can be very small indeed.

As this thread shows, people are reporting windscreens failing when the inside is hot and the outside cold, but, they are not reporting windscreens failing when warm water is poured on the outside while the inside remains cold.

As an aside, I've spent a significant part of the last 5 years designing, developing, analysing, inspecting, and testing structures made from glass like materials to withstand high mechanical and thermal loads. The low coefficient of thermal expansion makes the materials attractive for high precision, highly stable instruments, but, their brittle nature makes them very fragile.

De-icing with warm water - cheddar
I suggest it is not simply a matter of the two layers of glass seperated by the laminate being at different temperatures, rather sections of the glass (by surface area) being at different temperatures due to the inevitable unevenness in the application of the hot water. I.e. the same thing that cracks a glass tumbler if you pour boiling water into it when it could survive 200deg if heated evenly in the oven.

I have heard of car windows being cracked by the application of too hot water though warm water does a good job if you can drive off immediately.
De-icing with warm water - Number_Cruncher
>>I suggest...

My earlier post at 16:51 discusses this effect, and why it *doesn't* cause windscreen failure when warm water is poured onto windscreens.


De-icing with warm water - cheddar
My earlier post >>


Sounds quite reasonable though as I say I have heard of kettle (thus nearly boiling I assume) water cracking screens.
De-icing with warm water - Number_Cruncher
>>I have heard of kettle (thus nearly boiling I assume) water cracking screens.

We're back at the OP's original question.

I've also heard tales of it happening, but, I've not seen it happen, and I don't know anyone who I would trust who says it has happened to them. Urban myth? probably not, I can well imagine someone's screen has broken; but also, I would suggest, it's not a particularly large risk, particularly not if you only use luke warm water.

I'm sure you can crack screens if you use hot enough water, it's just a question of combination of any tensile stress being high enough and any existing defects being bad enough for fracture to occur.

The tensile stress required to grow the known cracks on my screen must now be quite small - the crack is 10mm or so in length, but, pouring water over it to de-ice doesn't make it grow.

De-icing with warm water - J Bonington Jagworth
"people are reporting windscreens failing when the inside is hot and the outside cold, but, they are not reporting windscreens failing when warm water is poured on the outside while the inside remains cold."

I wonder if that's to do with the curvature of the glass? The expansion stresses and strain (movement) may be more easily contained on the outside than the inside...
De-icing with warm water - Number_Cruncher
>>I wonder if that's to do with the curvature of the glass?

I don't know.

However, the glass usually only has significant curvature in one direction, so this wouldn't have any effect for cracks growing because of stress acting in the other direction.

De-icing with warm water - Steve Pearce
An advert currently running on the telly indicates the car heater could be enough to
open up existing screen damage as well as potholes.


I once had a small crack on the passenger side that had been there for months suddenly spread across the whole windscreen on a very cold night when I had had the front defroster on full blast for 10 minutes or so.
De-icing with warm water - slowdown avenue
the reason for not using water is , it then freezes on the ground causing a more dangerous situation
De-icing with warm water - Armitage Shanks {p}
The only thing I LIKE about my KA is its heated windscreen!
De-icing with warm water - component part
Another advocate of the hot water method. I take a jug of hot tap water-maybe 60c. A 2l jug is enough for me to do the whole car. My screen has a few noticeable chips in it but I've used this method dozens of times and no problems yet. I also used it on my previous cars and have never cracked a screen.
De-icing with warm water - Cheeky
Am I right in thinking it is only Ford group vehicles that have this great heated front screen feature? My X Type Jag has it, my wife's old 2001 Fiesta had it, yet my neighbour's top of the range Volvo V50 doesn't. Strange. Anyway, such a good feature, I wondered why other maufacturers hadn't cottoned on, unless Ford patented the idea...??
De-icing with warm water - dieselfitter
Not the same thing, but a colleague who lives in central Finland e-mailed me one morning to say his windscreen had cracked spectacularly on the drive to work with the heater on full inside and freezing rain outside.
De-icing with warm water - Stuartli
The cracked windscreen possibility probably goes back to the time of toughened, rather than laminated windscreen glass, which more often than not shattered when hit by a stone or sharp object.
De-icing with warm water - zookeeper
does having fully comp insurance mean you can get small cracks and chips in the windsreen repaired "free" or are there strings attached, ive seen them operating in supermarket car parks but i was only tpf&t at the time, now im fully comp how do i go about it? thanks .....zoo
De-icing with warm water - Dynamic Dave
does having fully comp insurance mean you can get small cracks and chips in the
windsreen repaired "free"


Direct Line now charges £10 for screen repairs.
or are there strings attached ive seen them operating in supermarket car parks


I asked the guy at my nearby supermarket to take a look at the chip in my windscreen. "Who you insured with?" he asked in his his best foreign accent. "Direct line" I reply. "Hmmm, don't deal with them, tell you what though, I can still do the repair for £20". "You gotta be joking" I told him, "I'll get Autoglass to do the job for £10".

When I spoke to the guy from Autoglass, he told me most of these supermarket fly by night operators don't have the proper kit to repair glass, and most of the time we're called out to rectify the work they've done.
De-icing with warm water - Devolution
Check your policy - most main well known insurance companies do offer windscreen repair and replacement on fully comp policies, but there are a few that don't. In particular some from online comparison sites; they may offer cheap deals but don't include any extra benefits whatsoever.

Normally the insurance companies only allow authorised companies to do the work in order to qualify for the free/cheap repairs and/or replace. Often this is Autoglass, and I'm sure I have seen their repair stands out and about in similar public places. Normally repairs are free and a full windscreen replace means paying an excess of around £75 only. (Was £60ish).

Unfortunately, Autoglass' huge advertising campaign means people who would normally leave a crack or ding, are now getting it done rather than leaving it, but at the same time increasing a lot of claims, hence some insurers now charging a repair excess as well.
De-icing with warm water - BobbyG
I may be imagining things, but I seem to remember a discussion on here some time ago about the benefits of cold water for defrosting rather than hot?
Not sure if it was in relation to clearing windscreens or maybe some other reason?

Can anyone remember this or am I totally losing my marbles?

FWIW this year I am a total convert to the hot water method at home. Although I still put an old sheet across the windscreen, I use the hot water to pour over the wiper blades and the side windows.

The Altea's wipers are parked in the vertical position behind a cover in the windscreen pillar which seems to have prevented too much deep freezing.
De-icing with warm water - Devolution
Can anyone remember this or am I totally losing my marbles?


I can. It comes up every winter or during spells of cold weather. Pretty sure I remember the discussion. If I'm wrong I'll join you in the marble hunt!
De-icing with warm water - AndyTheGreat
Like many others, I've used the hot water method for many years. Has the advantage of helping warm the screen to prevent misting on the inside as well. I use water from the hot tap, not boiling.

NumberCrunchers post was interesting, the only time I've known a screen to crack was when in a friends car, the screen already had a small crack which grew by 2 inches when the heater was put on it.
De-icing with warm water - daveyjp
Watering can of tepid water with a glug of concentrated screen wash does the job. No refreeze problems then.

If you are using a supermarket outfit for a repair make sure they are authorised to do the work by your insurance company. If they aren't expect a bill. Our local shopping centre has an Autoglass tent most of the year. I used them, provided my insurance details and no bill.
De-icing with warm water - Aretas
Cheeky - Someone told me only last week that the Ford patent runs out sometime in 2010
De-icing with warm water - henry k
In the past I have used warm water but now I am a convert to those trigger guns of fluid sold in Shell filling stations and the like.
A quick squirt along the top of the screen or windows and it trickles down and works very well. No icy patches left surrounding the car.
It is especially good in the far end of the works carpark at going home time when the kettle/ bucket is not available :-)
De-icing with warm water - rtj70
A quick squirt along the top of the screen or windows and it trickles down and works very
well.


Not for me today... after the warm water froze I tried the deicer. Didn't have much effect. I know it drops the temperature of the glass so the water just stayed frozen. Deicer said it was good for -15 deg C too.

I just made a few phone calls in the car whilst it warmed up ;-)
De-icing with warm water - Pugugly
Always the best way - leave dog in car and engine running and heater on. Druggies can try and take him on.
De-icing with warm water - rtj70
leave dog in car and engine running and heater on. Druggies can try and take him on.


Is it a Spaniel you have or have I remembered incorrectly.

Two years ago just before Christmas a neighbour left car running to warm up whilst they loaded presents for a family visit.... car was taken. Luckily for them they were covered on insurance but they had it spelled out the new policy with new wording would not have covered them. So they were very lucky.
De-icing with warm water - L'escargot
I just switch on my windscreen electrical heater. I wouldn't buy a car without one. I assumed all modern cars had them.
De-icing with warm water - Pugugly
As I say - it would be game on as far as the dog would be concerned - he is highly protective of his space in a car.
De-icing with warm water - Brian Tryzers
Doesn't the dog just raise the humidity and leave you with frost on the inside of the glass as well?

Idling the (Volvo diesel) engine doesn't work for me; even once it's moving it doesn't offer much spare heat till I'm just about out of town, four miles away.

What does work is a heated electric serving tray. Plug it in for eight minutes (timer if I'm organized the night before) and rest it on a towel on top of the dashboard. It gently radiates enough heat to clear most of the screen while I have breakfast, without humidifying the interior. A couple of well-placed hot water bottles can do the same job.
De-icing with warm water - craig-pd130

Hand-hot water from the tap in an old 2l milk carton, and a large window-cleaner's rubber-blade squeegee has served me well for the last 18 years with no windscreen cracking in any of our cars.

Pour on the water, let it melt the ice / frost, then wipe off the water. Clear windscreen that can't refreeze.
De-icing with warm water - L'escargot
If you haven't got an electrically heated windscreen, why not just use a hair dryer rather than warm water?

Edited by L'escargot on 05/01/2010 at 10:11

De-icing with warm water - pyruse
Using a hair dryer involves running a cable out to the car.
Using warm water is just a matter of filling a couple of plastic bottles from the hot tap; much easier.
Heated screens would be great if they didn't have those little wires in them - I find the wires a constant distraction, and they create funny effects at night; to the extent that I'd never buy a car with wires in the windscreen.
De-icing with warm water - L'escargot
Using a hair dryer involves running a cable out to the car.


Get a weatherproof outside socket.
Heated screens would be great if they didn't have those little wires in them -
I find the wires a constant distraction and they create funny effects at night ..........


I've had three cars with heated windscreens covering about 12 years of driving and not found them to be a problem. I admit that you can sometimes momentarily see the wires under certain conditions, but if you're looking through the windscreen and not focussing on it then the the wires shouldn't annoy you. I think that once you've made up your mind that they annoy you then you'll never be able to forget about them. I personally would never buy a car without an electrically heated windscreen.
De-icing with warm water - CGNorwich
"I personally would never buy a car without an electrically heated windscreen."

Unfortunately that virtually restricts you to a Ford. Most of my cars have been Ford but after the experience of owning a CMAX vowed never to buy another Ford. Now have an Octavia. All the heated windscreens in the world would not get me back into a Ford.
De-icing with warm water - L'escargot
but after the experience of owning a CMAX vowed never to buy another Ford.


It's not logical to rule out a given manufacturer on the basis of the experience of owning one particular car. Car designs and the manufacturer's employees are continually changing.
De-icing with warm water - CGNorwich
"It's not logical to rule out a given manufacturer on the basis of the experience of owning one particular car"

Might not be logical Mr Snail but there's no way Ford are getting any more of my money after that 'ownership experience".
De-icing with warm water - oilrag
Cos water is more efficient than air at transferring heat.

Faced with my wife`s old Punto out on the drive at 5am, doors frozen shut, covered in ice and snow frozen onto that - I have started using a watering can of warm water. It`s an older car of course, so not as bothered, but I wish I had used this technique years ago.
There`s no other way I can think of to get the door seals free, instantly - but of course, once you use water...

Edited by oilrag on 05/01/2010 at 10:43

De-icing with warm water - L'escargot
There`s no other way I can think of to get the door seals free instantly ...........


I'm never in that much of a hurry. You just need to allow yourself a few minutes to defrost your car.

Edited by L'escargot on 05/01/2010 at 10:49

De-icing with warm water - oilrag
Problem is though, you can`t get in to defrost it.

And at 5am with the old 1.9D braying like a donkey in an oil drum.. ;-)
De-icing with warm water - L'escargot
And at 5am with the old 1.9D braying like a donkey in an oil drum....


You're the first diesel owner I've come across that has admitted that diesels are noisy. My car's sump may be rusting but at least it's doing it quietly!

Edited by L'escargot on 05/01/2010 at 11:30

De-icing with warm water - oilrag
That sump! Again!

I have a tub of HMP grease and some rubber gloves, if you ever pass by, L`esc.... ;-)
De-icing with warm water - Pugugly
Steady Uncle Bryn.
De-icing with warm water - kithmo
I cracked a laminated windscreen once by squirting solvent on it to clean it on a hot summers day.
.
Keith
De-icing with warm water - L'escargot
That sump! Again!


:-D
De-icing with warm water - BobbyG
Why does it appear that no one simply puts a cover on the windscreen at night?
De-icing with warm water - Pugugly
I have two couldn't find either.....:-(
De-icing with warm water - JohnM{P}
Cars outside Ford Group with heated screend? From an earlier thread:
www.honestjohn.co.uk/forum/post/index.htm?t=69640&...f
it seems that Pimeras had heated screens, and that they were an (unorderable) price list option on the 2001 LagunaII. Oh, and I saw a 3Litre Austin (giant 'Landcrab') with heated side windows in the 70s...
De-icing with warm water - Brentus
We used to have a dehumidifier in an old house we had. In the morning the container was full of water, suppose you could say lukewarm (some might say ionised) it could have been both. For years used to de frost windscreen with this, screen never cracked.

Regarding these windscreen repair jobs wether by someone in the supermarket car park or a true professional. I'm almost sure i remember when doing annual quotes. Asked if i had made any claims and this would include this. However it does not effect the quote, so why ask then.

Edited by rtj70 on 05/01/2010 at 19:11

De-icing with warm water - madf
I would be interested to know if any of those who have used this warm water method live in warmer climes eg South England.. unlike us ignoramuses who live where mornings at -8C are quite common and -12C are possible and -15C happens..

Because if it only works down south,,, I will not bother.

My experience of really cold weather is that water on glass= frozen wiper blades and all that entails.
De-icing with warm water - commerdriver
if it only works down south I will not bother.


I used it successfully in Paisley (a quaint wee suburb of Glasgow) over Christmas, worked fine as long as the water was then cleared off before it re-froze, either by wipers or rubber blade of a scraper
De-icing with warm water - Brentus
aye went to tech there many years ago it does get nippy there.
De-icing with warm water - Group B
I would be interested to know if any of those who have used this warm
water method live in warmer climes eg South England..



Ive done it for years. Live in Derbyshire 200m above sea level, had regular
-6 to -9'c temps overnight here in the last few weeks.
I use lukewarm water only and do several slow, steady applications so it warms the screen up to clear it, demist it and use wipers before the applied water freezes.

The only time in 18 years I've had a cracked windscreen was years ago when my brother accidentally tapped my windscreen with a new krooklok I got for Xmas. It cracked very readily without any warm water having been applied.

Edited by Group B on 05/01/2010 at 20:37

De-icing with warm water - paul2007
Hi

when I lived in the north of the uk years ago, i regualrly used warm water - did the trick, cleared the ice in and out but started the car before watering screen other frost up.

however, the window seals deteriorated and resulted in water impregnation. on a summers day, driving without shoes my feet got wet - noted bottom of car was rusted - garage advised me that front and rear window rubbers perished because of me using warm to very warm water.

my neighbout twice cracked her screen as she accidentally used water that was too warm for the ice cold conditions.
De-icing with warm water - CGNorwich
"garage advised me that front and rear window rubbers perished because of me using warm to very warm water."

sounds a bit unlikely to me - surely would mean washing your car with warm water would have the same result.


"my neighbout twice cracked her screen as she accidentally used water that was too warm for the ice cold conditions."

So the only person so far positively identified as achieving a cracked windscreen by de-icing with warm water managed to do it twice - remarkable.

De-icing with warm water - Kevin
>on a summers day, driving without shoes my feet got wet..

Did you have the window open?

I really hate people who drive without shoes and leave the window open!

I have also reported PU to the RSPCA.

It is totally irresponsible to expect a dog to take charge of a vehicle without training and a valid license ;-(

Kevin...
De-icing with warm water - welshlad
just hazarding a guess here I dont have any scientific fact to back it up but i would be inclined to believe that this is something that is probably rooted in the days long since past when 'car glass' was just 'glass' and would have cracked just by looking at it funny.

De-icing with warm water - paul2007
my friend, the front screen has been laminated glass on most, if not all uk cars since mid 1960's
De-icing with warm water - Pugugly
Mid 60s ? More like the Mid-80s !
De-icing with warm water - L'escargot
Mid 60s ? More like the Mid-80s !


1981, according to this. tinyurl.com/yf3hbhq
De-icing with warm water - Brentus
Used some warm water this morning, got the blades going cleared no prob. No cracks fingers crossed.
De-icing with warm water - oilrag
It`s starting to look like a safe procedure isn`t it?

There will likely be gnashing of teeth by scraper and de-icer stockists and sales of `pink or blue` will plummet.

Edited by oilrag on 06/01/2010 at 19:45

De-icing with warm water - Stuartli
>>There will likely be gnashing of teeth by scraper and de-icer stockists and sales of `pink or blue` will plummet. >>

The subject of using tepid water has been raised a number of times over the years in these forums, but the advice given has not dramatically affected sales of de-icer aerosols to the best of my knowledge...:-)
De-icing with warm water - paul2007
Clearly recall my dads Zephr 6 having a laminated screen in mid 60's


here's more

capripower.co.uk/cci/caprihistory.htm


the americans were at the forefront and standard fir for fods in 1930's = model t.
De-icing with warm water - henry k
But the BBC says

"Windows: clear all snow and ice from the windscreen before driving. Don't use water to de-ice windscreens. Hot water can crack the glass, and the water will only freeze again on the screen or on the ground where you're standing."

news.bbc.co.uk/1/hi/uk/8443690.stm
De-icing with warm water - Stuartli
>>Don't use water to de-ice windscreens>>

As I've stated earlier, I've done it for years.

Currently the watering can (complete with rose) is permanently in the porch ready for use.

I did the car this morning before going out with the temperature at -2.5 degrees C and only had to ensure the windscreen remained clear by using the wipers immediately after pouring on tepid water. Note the word "tepid"...:-)

Biggest problem is that the ground is so cold it will take some time for it to thaw out and allow the snow and ice to clear away.

Edited by Stuartli on 07/01/2010 at 14:27

De-icing with warm water - Sofa Spud
I've always used warm water - for over 35 years. My parents did too, and my father worked for a luxury car maker.

I've never heard of anyone breaking a screen through using hot water, though I suppose if you used boiling water and the outside temperature was -20C, then it might.

Anyway, the only way I've ever cracked a windscreen is when I was changing a wiper blade and the metal arm slipped from my grip and snapped back against the screen, right in the driver's line of sight....aaaargh!

So on my evidence, statistically you're more likely to break a windscreen while renewing a wiper blade than while de-icing with hot water!!!

Edited by Sofa Spud on 07/01/2010 at 15:46

De-icing with warm water - zookeeper
a couple of squirts with alcohol gel may be worth a try , i was thinking of coating the windscreen whilst its clear to prevent a build up of snow/frost overnight....
De-icing with warm water - Leif
But the BBC says
"Hot water can crack the glass and the water will only freeze again
on the screen or on the ground where you're standing."


Naah. I fill a large anti freeze container with warm water, and pour on enough to ensure that the screen warms up above freezing. It also melts the ice on the inside of the wind screen. I don't know why I only started doing this a week ago as it beats running a car engine, wasting fuel, and creating pollution, whilst I scrape away at the ice.
De-icing with warm water - CGNorwich
Welcome to the converts Leif
De-icing with warm water - Pugugly
Anybody use that silly night before rubbish ?
De-icing with warm water - Bromptonaut
Anybody use that silly night before rubbish ?


Tried it twice. First time it worked OK. Second the forecast was wrong and it didn't freeze - took ages to get rid of the smears!!

Edited by Bromptonaut on 07/01/2010 at 21:24

De-icing with warm water - Alby Back
Yes but it didn't work. He's nearly 10 now......
De-icing with warm water - The Melting Snowman
It's an old wives' tale as far as I'm concerned. For many years we have put warmish water on our screens and never had a broken one in over 50 years.

If you put very hot water on a cold screen then you're asking for trouble.

These days I use a 3KW fan heater in the car run from a 13amp extension lead. 10 to 15 mins has all the windows clear and the car interior nice and warm. Also, crucially, as the interior is warmer when one gets in the car one's breath doesn't cause the windows to steam up nearly as much. There was a thread on here about two weeks ago detailing using a fan heater. Observe the sensible precautions detailed in that thread. If you can be bothered then you can rig up a timer but I generally just plug it in when I want it.

Another useful thing that you can do that one doesn't see so much these days is leave a sheet of newspaper on the screen trapped under the wipers. Or an old blanket - which is probably better - and trap it in the front doors to secure it. When it gets a bit grubby I place it in the laundry basket and it miraculously appears washed and neatly folded in the airing cupboard the next day. :-)

Final thoughts: this winter the Ford Quickclear screen really has been brilliant - I would never buy a car without one now. If the ice is really thick then I still throw a bit of warm water on it but the elements stop it re-freezing. And the Swedes know a thing or two about car heaters - our Volvo heater is fantastic and is blowing hot air after less than a mile. Combined with nice heated leather seats it's a comfortable place to be on a cold morning. 25 MPG not so good but it's a big, heavy car and its reliability and build quality even at 160000 miles puts some other cars we've had to dismal shame.