What can cause the reservior to overflow from the radiator when the car is stopped? Car is not overheated. It is almost like the fluid backups - could it be the thermostat closing and causing a backflow to the reservior???

 

you might have a leak somewhere in your coolant system. ck your car out when its cold. do a pressure test. i had the same problem. It turned out to be a bad water seals. hope your has just a leak somewhere.

 

If there is too much coolant, the car will kick out the excess. There is a release hole near the reservior, so when you over fill it, it has a place to push out the excess.

Do you have any other problems beside the coolant on the ground? Check the coolant levels, if they are fine, don't add anymore and see if you are still leaking after the next drive.

 

I answer this question atleast 1 or 2 times a week. 90 pct of the time its a cracked coolant container. It may not looked cracked, but it probably is. The symptoms are:

You drive the car, nothing leaks. You stop the car and all of a sudden a few minutes later it leaks a cup or 2 or 3 all over the ground. When the car cools off, you can fill the coolant container up and it will not leak. I think the crack expands with the heat and lets the coolant out.

my 3 cents.

 

Thanks guys ZeroBanger you had it on the nipple!