Fredbird

About a week ago my 91 l98 started to run poorly after driving it for extended periods of time.

I stared to suspect that the drop in power after the engine had heated up was possibly due to a blown head gasket.

I removed the radiator cap and started the engine. After several minutes of the engine running and the engine heating up I started to see an occasional bubble come to the surface. Does this indicate a blown head gasket?

I am not seeing coolant in the oil. I will pull plugs tonight to see if they are wet. But the engine also doesn't seem to have a hard time starting which I would expect from wet plugs.

What else can I check to know for sure?

John A. Marker

Check #7 and #8 plugs. If you find one that is really clean...chances are that you have a blown gasket. There is a water passage at the rear of these cylinders that is only about 1/8" from the cylinder wall. The gaskets tend to blow out in this area and the coolant will spray into the cylinder and doesn't get a chance to mix with the oil.

A better way is to take it to a shop. They should have a tester that then can place in the radiator to test for exhaust gasses in the coolant.

Good luck with your FUTURE gasket change project.

Fredbird

I will check those plugs later tonight... I really hope I'm wrong...

I am not seeing white smoke or anything.

I did see that tester that can check for combustion fumes in the radiator. I will take it to a friend of mine and have him check it out.

65Z01

I was going to suggest a pressure test of the radiator; also a compression check of each cylinder.

Fredbird

Yeah, I will get the radiator and cyl. Compression check done this week. Didn't get to check the plugs last night but I will try checking them later today or tomorrow.

If this ends up being what I fear... Anyone got a good guide for changing head gaskets?
Also, what else should i do since I will already be tearing down the engine that far?