I made a stupid mistake this week, I put some summer windshield washer (Temperature > 0°C) in the my car. It's currently -14°C outside so you can guess the fluid is completely frozen. I don't have access to a heated garage to leave the car inside for some time as suggested here. The tank was pretty empty when I filled it up so it must be like at least 95% summer mix in there.

Can I expect some damage? But more importantly is there any other way to melt the frozen windshield washer from the tank, the pump and the line?

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    Anything you can get which can heat the fluid will work. Someone suggested heating tabs (like you'd put in your pocket), or you could use a blow dryer on it. Thing is, at -14°C, if you are only spot heating an area, when you leave it alone, it'll probably freeze back up. If you let the vehicle sit with the engine idling for a while it may also unfreeze it ... just don't expect it to thaw if you're driving it around. You are trying to build up heat under the hood. Just suggestions. Commented Jan 14, 2016 at 2:17
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    Perhaps if you left the engine on for an extended period of idle time it may begin to thaw it out a bit. If you could get it just a bit slushy that could help. As well you could try pouring anti-freeze or a bunch of salt into the reservoir and that could thaw it out over time. Letting it freeze too long, the ice will expand and rupture the reservoir. Commented Jan 14, 2016 at 3:44

4 Answers 4


If you are at least slightly handy with tools (or have a nice friend who is) then it probably wouldn't be too hard to remove the tank c/w pump from the car and take it inside to the warmth and let it defrost in the bath tub and maybe even run some warm water over it. This may fix the tank and pump, but line is harder. Possibly fill tank with winter fluid and take it for a drive to try and defrost the line.

  • That's a really good idea. Best one yet IMO. What can it be? 3 maybe 4 10 or 12mm bolts, disconnect two hoses? Commented Jan 14, 2016 at 7:38
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    This morning I took the tank off before going to work it will have all day to unfreeze. The only down side to this idea is that I'm going to make a mess (the tank will drain). Else it was pretty easy and quick job 2x 10mm bolt and disconnect the pump. It took me like 5min at -19°C as per writing this...
    – Rémi
    Commented Jan 14, 2016 at 13:05
  • There you have it. Commented Jan 15, 2016 at 7:07

LOL - I literally just dealt with exactly the same problem too. What I did is stick a roof heating wire inside the tank and plug it into a wall outlet for 12 hours.

Another solution from a friend was to boil water and continuously pour it in the tank until the ice is melted, then normally drain all the water using the pump to spray it all out and then fill the tank with -35c windshield washer fluid.

Those summer windshield washer fluids should be banned from north countries, seriously :P


I did as per duckboy answer, I took out the windshield washer tank of the car and took it inside to let it unfreeze. This was a really easy job (look for your own car how to do it) but in my case (a vw jetta city 2009) it was 2x 10mm bolt, an electric connector to the pump and the windshield washer hose comming out of the pump. It took me about 5min to have the tank in my hand out of the car.

If you are going this route I suggest you have some plan ready to avoid making a mess inside with the windshield washer fluid (maybe put it in the bath, a sink, or a larger bucket) because in my case this step wasn't done so I had to improvise at work. I took several plastic bag but there still was fluid comming out of the bags.

I will reinstall the tank in my lunch time later today and I will see if I need to do anything else to unfreeze the hoses (I don't think because there was a rather larger spot of windshield washer under where I was parked so the lines might have just emptied themselves while it was still hot under to hood).

If you are tempted to let the car idle to built up heat to melt the fluid (as per DucatiKiller suggestion in the comments to the question) be aware that after 9+ hours inside, the fluid wasn't all liquid so this might not be a good solution.


Put a fish heater in the tank then when It melts use a blow dry or something warm on the line. After had a bottle of gas line antifreeze to it that why it won’t freeze again

  • you really risk damaging the fish heater, they are not made to be working that hard and also should be submerged when heating.
    – Rémi
    Commented Oct 9, 2020 at 13:26

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