my 95 sedan deville with the 4.9 is loosing coolant SLOWLY. It takes about 3-4 months to lose about half the coolant. I believe it may be a small hole in the headgasket due to overheating almost 2 years ago. There are no puddles or marks on the driveway where i park so I think its gettin burned up. can anyone give me a resonable price to replace the head gasket, or any other ideas where there may be a leak.