My car seems to be leaking coolant. From what I can tell the car warms up and the water expands and fills the overflow tank and then the overflow tank overflows. When I park the car and the engine cools it sucks the coolant back out of the overflow tank but beacuse it spilled over there is not enough to refill the coolant system. Any ideas as to what I can do? Thanks.

AdamP

 

OH BOY THAT IS BAD!!!!! Either your thermostast is stuck closed, or your engine is going bye bye

 

If my thermostat was gone then my engine would over heat, and if there was a seal gone in the motor it would preasurize my coolant system and dump all my coolant out. I am not loosing lots of fluid only enogh so that I have to refile every couple of times I drive it. So I don't think my motor is gone and I realy doubt my thermostat is stuck closed.

AdamP

 

If you are absolutely sure that the leak is from the overflow tank overfilling, then it has to be the cap on the AST. If the cap isn't holding pressure it will vent into the overflow bottle when the engine is warm. Make sure the coolant system is "burped" and that you have enough anti-freeze as well. Maybe the there isn't enough and you are boiling prematurely.

I had a small leak last week I thought was coming from the overflow tank, but turns out the radiator was leaking. I replaced it Monday.