When I shut the engine off after a good drive, the coolant reservoir bubbles like mad. But if I start the engine back up, it stops bubbling immediately. It never overflows, nor does it overheat. Ideas?

 

My 04 does the same thing...


Last time it happened I found a leak from one of my heater hoses after I started investigating. I can only assume it was sucking in air into the coolant system as the engine cooled and that air was traveling to the overflow bottle and causing the bubbling, but I honestly don't know...


I've looked all over the engine and everywhere else this time and haven't found any leaks. Not loosing coolant, heater works, not overheating at all, so I've just started living with it. Nothing else seems wrong, so I'm not going to fix it if it isn't broke lol

 

Could be exhaust in the coolant. That could be a head gasket, but they don't usually go bad.

 

This was my fear, but it seems highly unlikely that the only symptom it would exhibit is this and nothing else. Guess I'll have to break out the mighty vac.

 

If the engine isn't running, where exactly is this exhaust coming from?

 

Good point.

 

Hookep up my Mighty Vac today and found no keaks. System seems to be tight. At this point I suspect the radiator cap may be the problem, even though it's an OEM part less than 6 months old. Going to buy an el cheapo brand and see if anything changes. Will keep you posted.

 

Check the mix of the anti freeze it may be over diluted or expired. I filled my system with hose water during one step of a flush process and after bringing the engine up to 200 degrees my reservoir boiled when I shut it off. I was concerned for a second then I realized that's why you don't put just water in there.

 

Will do.

 

Your engine actually gets hotter after shutting it off for a bit. nothing flowing and no fan