I am putting about 2 qts of coolant in my car everyday. I've replaced the expansion tank and hose. Lots of foamy bubbles in the expansion tank returning from the motor. After driving for 20-30 min it starts loosing coolant at a very fast rate. I was told the system might be getting over pressurized from a head gasket leak? I have no white smoke coming out the exhaust, oil is not milky and coolant is clean. The car also runs great as long as it has coolant in it. It has also over heated a few times very briefly through this. The only place I see coolant is around the reservoir tank and it drips into the driver wheel well. Nothing wet anywhere else. Any thoughts?

 

you can buy an HC (hydrocarbon) test kit that measure exhaust gasses in the coolant as a head gasket test. Have you noticed if the upper radiator hose gets rock hard once the engine is running for a few? Did this problem start before or after you replaced the expansion tank?

 

You won't see white smoke until it gets really bad, the converter is so hot it evaporates the coolant, Volvos generally do not get coolant in the oil with a damaged head gasket like some other brands do - and don't leak oil into the coolant (unless the oil cooler leaks).

As others have suggested a HC test on the air above the coolant in the reservoir is a good diagnostic tool (there should be no HC present), or a simple pressure test (does pressure build up quickly under load) You should test the cap to make sure it holds pressure also.

Unfortunately that's a Volvo that does not have a low coolant sensor. And it's been overheated more than once, and you are loosing coolant, and ----------------