Now that temperatures are dropping below freezing, I decided to fill my wiper fluid reservoir with winterized fluid. I used almost an entire bottle, so it must have been almost empty, but there was definitely some summer fluid (without antifreeze) left in there.

However, after I filled up the reservoir with the new stuff, I realized that the bottle of leftover summer fluid I was keeping in my trunk was frozen completely solid! If it was frozen, so must be the fluid in the system.

Would the frozen fluid cause any damage? Will the antifreeze in the winter fluid cause the frozen fluid to melt?

4 Answers 4


As already mentioned - no permanent damage is expected. Leave your car in a warm parking lot (underground or heated) for a couple of hours. Summer fluid will melt and you could safely use sprays to drain it from connecting pipes.


Doesn't seem to cause any damage, at least on my cars. My washer fluid freezes inside the system every Winter and I've yet to have any problem (one car is 21 years old and the other is 17) with the washer system (even accidently trying to use it a few times each Winter when I forget that it's frozen).


I've had 1999 RAV4 and I left it with summer washer fluid couple years ago. Then I refilled it with winter fluid like you did. The damage I got is a rear spray didn't work, because I got a hole in the hose that connects spray thing to the main reservoir(most likely because of expansion of fluid in the hose). So, when I tried to wash my back window, all of the fluid resided on the ground.


if your washers don’t work, first check to see if you’re out of fluid, but if not, don’t think that just because the tank isn’t frozen that the jets aren’t, either. It’s cold sitting up there on that hood. If you can get near an electric outlet, a hair dryer can be used to defrost them.

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