Head gasket or oil cooler

[RBMD]

Need help. My 98 Catera is losing a gallon or more of coolant per week with no drips whatsoever. My mechanic pressurized the coolant system and saw white exhuast. Says it's the head gasket. Could he be wrong and this be from the oil cooler? There is no oil in the coolant as far as I can tell- at least in the plastic tank but the level falls and I might not see it. Thanks
Rich

[guardian]

I agree with your mechanic.

Before you rip both heads off you might want to run a compression test, in order better to localize the problem.

Of course if you compression test all six cylinders finding good outcomes across the board, then both your mechanic and I might just be wrong.

Good luck!

[sirmqc]

Wouldn't you want to check for coolant in the oil? I don't know about the Catera, but on other cars I've owned/been around, white foamy oil is a sure sign of head gasket leak. I'm no mechanic.

Any harm in trying a stop leak coolant or oil additive before tackling such a big job???

[sirmqc]

Maybe flush the radiator if you do end up replacing the gasket.