I've tried all kinds of commercial sub-zero windshield liquids but am so far satisfied with none, because of the following reasons:

  • They all seem to freeze below about -5C. Or at least become thick enough to jam the system. I've had the issue investigated by the dealer's mechanics, but they couldn't find anything wrong and suggested it was a low quality liquid (they claimed to have seen some on the market). I've tried different brands since, but for the last 2 winters there has been no windshield washing below -5C (approximately).
  • They all stink. Not so much a problem for me, but my wife minds, so that's a good enough reason for me. Ideally the liquid should be odorless, but something faint and/or pleasant would be acceptable too.

What & in what proportions do I mix up to get a good windshield washing liquid? I'd like to avoid methanol and other highly toxic chemicals if possible. (Also, what keywords can I use to find information about this on Google?)

  • I've been told be some older mechanics that just pouring in some rubbing alcohol into your reservoir can help lower the freezing point of washer fluid. I can't say whether or not it would work well, but it's something easy to try that you're likely to already have.
    – agweber
    Commented Jan 13, 2012 at 20:55
  • 2
    I've been using the RainX washerfluid for a few years now. It hasn't frozen yet for me, even at 5F (-15C). As a plus, it also keeps a nice coat of RainX on the windshield.
    – jwernerny
    Commented Jan 17, 2012 at 15:28
  • Doesn't seem to be available in my country (Latvia). :(
    – Vilx-
    Commented Jan 17, 2012 at 15:48
  • RainX washer fluid is great stuff! Commented Jan 25, 2012 at 5:28

4 Answers 4


Short answer: you almost certainly bought a bad bottle of fluid with a low methanol content. Worse, it might have been fluid with some sort of glycol rather than methanol (possibly causing it to gell up on the windshield or at the nozzles). -5C isn't terribly cold (unless you're in an open high wind environment).

There are people that like to jabber about things like making their own windshield wiper fluid. I would read the comments on that thread with a skeptical eye. However, all of those words do illustrate that there are some critical points:

  1. You really have to have methanol in the windshield wiper fluid.
  2. It's not cost effective at all to make your own fluid.

One of the recommendations that makes a bit of sense is to add additional methonal to the reservoir to top off the concentration already in the fluid. That should keep the freezing point low.

In the end, I'd tend to go with the bad fluid theory. It gets colder than -5C here in the winter regularly (not this crazy winter, admittedly) and I've definitely been disappointed in some fluids.

  • I tend agree with it too, though it is peculiar that from half a dozen brands none were any better. Can there be some permanent residue from old liquids? Also - I realize that it will not be cost-efficient, but better that than no liquid at all.
    – Vilx-
    Commented Jan 13, 2012 at 13:33
  • @Vilx-, there absolutely could be some sort of crud in the lines. You might also want to check the nozzles - I've accidentally clogged those with car wax in the past.
    – Bob Cross
    Commented Jan 13, 2012 at 16:15
  • How do I check those things, and if they were clogged, wouldn't I have problems all year round?
    – Vilx-
    Commented Jan 13, 2012 at 20:36

-5C is not cold at all. It's -5F here today (-20C) and about this time last year was -27F (-33C). The commercial fluid with antifreeze has been fine. I'd expect regular washer fluid to be fine down to -2C or -3C, as it's not pure water and the detergents should lower the freeze point.

Are you absolutely sure you bottles you've been buying contain "Antifreeze"? Have you drained your reservoir before adding the new fluid? If it's mostly summer washer fluid and you add the winter fluid, it will behave mostly like summer fluid.

If it's neither of those, perhaps it's evaporation. Since the antifreeze used is an methanol, the boiling point is fairly low (65C, but we've all seen denatured alcohol evaporate off the counter top at room temp...). If the weather or your garage regularly get warm, I suppose it might be possible that the alcohol is evaporating out of the washer fluid. Make sure you have a tight fitting cap on your washer fluid reservoir. But I suspect it's either not really "washer fluid with antifreeze" or you aren't draining the reservoir first.

  • I'm pretty certain I pour stuff from bottles that have labels in the -15C to -20C range. And I always empty the reservoir before refilling, especially when transitioning from summer to winter liquid (meaning that I wait until pressing the switch leaves my window dry). The cap isn't particularly tight, though it's not exactly loose either. Just not hermetic. But I find it hard to believe that there could be a fast enough evaporation to make a difference.
    – Vilx-
    Commented Jan 17, 2012 at 22:04
  • Could it make a difference that it's a different brand every time? It's something I'm going to test out now - sticking to the same brand all winter long. My theory is that maybe they each use a different antifreeze, and the mix creates problems (I don't believe that the reservoir can be 100% emptied without surgical invasion).
    – Vilx-
    Commented Jan 17, 2012 at 22:07
  • You shouldn't need 100% empty, just enough to reach your freeze point. Making up numbers, lets say a 10% mix of antifreeze to fluid protects to -20C. A 20% mix might protect to -30C. If you pour a 10% mix into a partially full tank, you might end up with something like a 5% mixture and get maybe -10C. If there's just a splash at the bottom, it shouldn't make a difference. That it's different brands is what made me question your diligence. Maybe one brand has a poor mix, but they all can't. And I've never heeded brands and it's much colder here. Sounds like you're doing everything right.
    – bobpaul
    Commented Jan 23, 2012 at 19:42
  • Well, that's what I figure too - they can't ALL be bad. But then - why have none of them worked? Well, will see if sticking to the same brand helps. It's not very cold yet (only about -4C) so I haven't had any problems yet.
    – Vilx-
    Commented Jan 24, 2012 at 8:49

I live up in the north, and we see temps much colder than -2C. I've found that the washer fluid the dealers use is subpar for nearly everything below freezing. It might spray sometimes, but it will ice up on the window, especially when it's far below 0C. I suspect they water it down or something.

I've been looking around for a solution and have settled on purchasing some washer additive next time I decide to make an order of car products.

I'll probably get some of this Wurth additive when I do purchase some. I suspect there are other additives, but if you're having issues with the lines being frozen already, you may need to get your vehicle into a warmer garage to thaw and run some fluid through the system until you have enough of the anti freeze blend mixed in.

I've also heard of some more expensive brands of washer fluid that are good to much lower temperatures. But they seem to be quite a bit more expensive than the additive.

There is also a third type of de-icer I've seen that you simply spray on your windows when you park

  • Hmm, the icing on the window has also been a permanent problem. Do you mean that a quality liquid doesn't do that? O_O
    – Vilx-
    Commented Jan 17, 2012 at 22:09
  • Well it really depends on how cold it is outside. If it's -30F or lower you'll probably be hard pressed to find something that won't freeze on a windshield that hasn't been warmed up. But there are some De-icer sprays that are supposed to keep frost from forming on your window when sprayed on before you park your vehicle for the night. I also found a few homemade recipes on instructables and Consumerist
    – Philter
    Commented Jan 18, 2012 at 17:38
  • If it's -30F (-34C), I'll stay home. :P But if I can get it to not freeze down to 0F, I'll be impressed nonetheless. Checked out those recipes, they still rely on alcohol. Looks like that's as far as I'll get...
    – Vilx-
    Commented Jan 19, 2012 at 8:54
  • Yeah, alcohol is probably your best bet, unless you want to buy some of those washer additives. The fluid other people have been talking about is probably something like this which says it's good to -34F. And this Heet aerosol is the spray on stuff I was talking about
    – Philter
    Commented Jan 19, 2012 at 14:05

just add vodka to lower the freezing point.. Or isopropyl alcool

Anyway any alcool will lowe the freezing point (ethanol,metanol...)

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