Oops. I put wiper fluid in coolant.

Jon Holcombe

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Dec 1, 2015
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I know there is a lot of great vehicle knowledge here. I am engine illiterate. I just poured about a 1/4 or less of a jug of windshield wiper fluid into the coolant reservoir of my wife's Subaru. As of this writing, I have not conveyed that information to her and let her drive off to work. I'm ascared, not because of what might happen to her engine, but what might happen to me if she finds out I screwed up her car. Does her system need to be flushed and refilled?
 

1Jerseydevil

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Feb 14, 2009
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No, nothing will happen, rest assured. Wiper fluid is mostly water with a little alcohol for freeze protection. The amount you used is minimal. You could even fill the entire system with washer fluid, but it's not suggested as there are ingredients in antifreeze for water pump lubrication, antifoaming and corrosion resistance not present in washer fluid.

Today's radiators have a plastic fill jug similar to the wiper jug. There is a full line about halfway on the jug. This is for expansion when the fluid in the radiator heats up. When the radiator cools and fluid contracts it's drawn back from the jug. The worst that will happen is the jug will overfill with fluid and push out of the cap. If you see fluid leaking under the car don't panic. When the fluid is cold, take a turkey baster or similar and suck the radiator fluid in the jug down to the marked fill line again.
 
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old jersey girl

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Jul 26, 2017
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I know there is a lot of great vehicle knowledge here. I am engine illiterate. I just poured about a 1/4 or less of a jug of windshield wiper fluid into the coolant reservoir of my wife's Subaru. As of this writing, I have not conveyed that information to her and let her drive off to work. I'm ascared, not because of what might happen to her engine, but what might happen to me if she finds out I screwed up her car. Does her system need to be flushed and refilled?
Clearly you have your marital priorities in order. ! Her car should be fine as mentioned in previous post. Finish topping off the windshield wiper fluid, let her thank you for that, don't mention the goof.
 
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old jersey girl

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Jul 26, 2017
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No pictures this time. Just a strategic omission of irrelevant facts. She just feels good about the fact that I topped off her wiper fluid before a predicted snow storm. Why change her image of me from "helpful caring husband" into incompetent nincompoop?
Because 46er is right--- the omission will come back to bite you in the ass. A humerous reference with an admission of fallability is endearing. Also it reminds her 1) of one more thing she doesn't have to do and 2) that HER husband doesn't exhibit the usual male arrogance about all things mechanical.

I'm girl enough to remember how annoying that assumption is from when I was car racing!
 

Boyd

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Let's say somebody admires one of your photographs and wants to know more about you. Guess what comes up in a Google search? And what if that person is a friend of your wife's? ;) Better tell her. Otherwise, delete this thread (as the person who started the thread, you can also delete it).
 

Jon Holcombe

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I don't think she would care as long as I did not damage her car. I was smiling when I posted this, and it is a relief to know from mechanically inclined guys and jersey gals that I did no harm. I may tell her about this post because she would get a kick out of it. Thanks for all the great advice everyone.
 
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Zach McGarvey

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Feb 11, 2018
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You guys already settled this, but...

1. If you do nothing, nothing bad will happen.
2. If you want, normally the overflow bottle is either a slide-in fit or retained by one bolt. Remove it and dump the contents out. Replace with antifreeze.

Fluid is only drawn from the overflow tank as the engine is cooling and the volume of pressurized coolant in the radiator, hoses, and engine is contracting.