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Frozen windshield - deicing with hot water

I've recently moved to western Washington from Southern California and having to scrape icy windshields is a new (and very painful experience). How risky would it be to pour hot water over the windshield rather than using a scraper. I'm afraid it would crack the glass if the water is too hot, but there must be a "safe" temperature.


  • edited December 2009
    While pouring warm (not super hot) water on a windshield which is merely western Washington cold is probably not going to crack it, I would strongly suggest you just invest in a nice ice-scraper. Scraping the windows with a decent scraper should take a minute or two tops-- probably less than the time it takes to bother with the tea kettle.

    I personally like the scrapers with the copper blades.
  • edited December 2009
    I would not use warm water let alone hot. They make ice scrapers for that kind of thing. BTW most cars will warm up in a few minutes and will start warming the window without any outside help. Letting the car warm up itself will mean the engine will also be a bit warmer by the time you move out into traffic.

    Note: I is still best to drive the first few miles at reduced speeds (Avoid I-5 ... OK during rush hour you can do I-5 as it will be nice and slow). You need to allow the other parts of your car, like the suspension system to warm up also before driving at freeway speeds.
  • edited December 2009
    After you crack and replace 2-3 windshields post back on correct temp-get a good scrapper!!
  • edited December 2009
    Spray some of the winter (-20F) windshield wiper fluid on your windshield and let it soak for a few minutes. This will get the ice off.
  • edited December 2009
    I've seen a windshield crack when hot water was poured on it.

    I've never seen one crack when warm water was used, however I have heard enough stories about windshields cracking with warm water that I would never use it.

    As others noted, invest in a good scraper and let your car warm up for a few minutes so your defroster can help.
  • edited December 2009
    If it isn't too cold and the ice on the window shield isn't too thick, you can use the windshield wiper sprayers to knock the ice clear. In my experience, this only works down to maybe 20F. Other than that, warm the car up until you have a reasonable clear area. Then maybe you can finish the job with the windshield washers.

    The windshield washers will not help much with ice on the inside of the windshield.

    And sometimes, you just have to scrape/chop/hack the ice off.
  • edited December 2009
    I wouldn't do it. In addition to the risk of cracking the windshield, you're going to get a lot of water on the wipers or the area where the wipers sit, which will freeze up and cause other problems.
  • edited December 2009
    Think off it this way,are any of your neighbors throwing hot water on their windshields? no, I didn't think so.
  • edited December 2009
    Here's a simple solution: Turn your defrosters on high and wait for a few minutes. Ice scrapers tend to scratch the glass and using the windshield washers just wastes fluid and chews up the wiper blades.
  • edited December 2009
    remember your engine must be warmed (in order to provide the warm air to effectively loosen the ice) and now we get into the "letting the engine idle to warm up argument"
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