When my "engine coolant low" light came on, i made the mistake of putting Antifreeze where the brake fluid tank is located o.o I've added Antifreeze before on my car when I first came accross this light, and the second time around I felt confident enough to not look at the owner's manual to verify that I was putting antifreeze in the right tank. I took my car out for another spin and the light came on again, and that was when I realized I had put Antifreeze where the brake fluid goes. The car still works with the antifreeze/brake fluid mix and i'm still able to brake normally. But I figure eventually my baby('99 Jaguar XJR) is gonna break down on me because of my stupidity (hopefully not soon). Will this be a serious problem in the future? Thanks again for your supportVery Respectfully, -JanuarXKR

 

Without knowing the exact chemical process that will occur, I can assure you it won't be good. I've heard of simply using Dot 3 fluid with Dot 4 with the result of sludge in the lines, requiring all lines and brake booster needing replaced.

I'd get a flush done ASAP, as you have no idea if it will harm fittings, lines..effect hydraulic properties, some sort of chemical reaction... do it soon.

 

Hold on for a second...

Okay sorry, but this is pretty funny. On a serious note, your brake system will need to be flushed (all of the brake fluid completely removed) and refilled. This is not something you could do on your own. I've done it a couple of times and it's a big job. Then the brakes have to be bled after and this requires special tools.

If you leave the coolant in there, it could end up ruining the brake calipers, brake master cylinder, rubber brake hoses, and other components – leading to brake failure. Definitely stop driving the car, it is going to make it worse. Get it into a dealer or independant shop and tell them what happened. Brakes are something you don't take chances with.

 

Also if it were my car I would suck all of the fluid out of the master cylinder with a turkey baster and refill it before even driving it to the dealership. If your car has Brembo calipers and you ruin those, your looking at a $2,500 replacement bill. Not covered under warranty because of negligence. If your car is under warranty, you really might just consider towing it there so you don't void your brake warranty by driving it.

 

Yeah whiteSTR, i gotta agree with you. As i look back on it.

Thanks for the tips!