10-21-11, 09:27 AM
My 94 STS has a bad head gasket. Lot of white smoke on first start up but smoke goes away after about 2 minutes. Car does not overheat yet. My question is this- how can I tell which head gasket is bad? If car had true dual exhaust, I would be able to tell which head was bad. If I disconnect exhaust at cat, do you think I would be able to see which head smoke was coming from? I was also thinking of removing the front O2 sensor and see if smoke comes out from there. If I have a bad front head gasket, I may just repair that head so I can do it while engine is in car ( I know, both heads should get done).
10-21-11, 11:20 AM
Disconnecting at the cat won't work the exhaust from both heads has already joined at the 'y' pipe from the the manifolds. Can you pull spark plugs after letting it sit and cool down and peer into the cylinders?
10-21-11, 11:49 AM
Leak down/compression test?
10-21-11, 11:57 AM
I just pulled the front O2 sensor and started it up. Some smoke came out but not much. Still coming out exhaust. Both head gaskets have to be changed. I might try and sell as is or I'll just stud it in the spring. Other than the head gasket, car runs and looks great. New tires all around and all new brakes. Too nice of a car just to get rid of for peanuts.
Just pull the plugs and look at them. The leaky cylinders plugs will be clean. The difference will be very obvious.
10-21-11, 12:42 PM
How much, how often, do you need to add coolant to maintain the proper cold fill level ?
10-21-11, 01:39 PM
Get the work done correctly. You don't want to do this twice.
For a 94, check the throttle body / EGR passage for coolant intrusion, too.
10-21-11, 02:45 PM
I have too add about a quart of coolant once every 2 months. How would I check that EGR coolant passage?
10-22-11, 12:25 PM
In my opinion it does not really matter which head is leaking? Are you not going to replace both of them anyway? I mean with such a labor intensive job do you really want to do this twice..