reasons to believe i have a head gasket problem: (B230FT)
-loss of coolant. after about 2 days of driving, the expansion tank is empty. often i can see the coolant in the hose from the expansion tank. the coolant is never much lower than the amount in the expansion tank, no matter how long i wait to re-fill (up to 2 weeks).
-there is some type of grey residue (i am reluctant to say oil) in the expansion tank.
-since my last oil change, about 3k miles ago (i run synthetic) i've lost about 3/4 of a quart of oil.
-engine overheated (lower rad hose popped) in august or september last year.

reasons not to believe i have a head gasket problem:
-there is no sign of coolant in the oil. the oil cap has nothing but good looking oil on it after driving.
-while on cold mornings there is some white smoke from the tail pipe, it goes away rather quickly and is nothing more exorbitant than any other car i've observed. i have observed no smoke out the tail pipe otherwise.
-i just checked the spark plugs. they all look the same.
-the car is pretty peppy, and has been running well since the overheat.

i replaced the turbo (blowing oil past seals) in january. all cooling system hoses are new as well as new expansion tank. i have no idea how old the radiator is.