1998 GMC Jimmy bad head gasket symptoms

LUNAISAAC

MEMBER
1998 GMC JIMMY
6 CYL
4WD
AUTOMATIC
165,000 MILES

I had my jimmy parked for week it ran fine before that I started it and it started ideling very rough I drove it and warmed it up but no change like a bad misfire I changed pcv valve checked all vacuum hoses good changed engine control module, coil, and spark plugs my wires and distributor are only a year old it did the same thing I noticed noticed a coolant leak started right below the exhaust manifold nowhere near any hoses checked oil but no water in there and car not overheating yet could a bad head gasket be my problem. Would like to know before I buy head gasket set and tear it apart

2 Replies

BILLYMAC

MECHANIC
2,204 POSTS

Hi
yes a coolant leak there, could be a head gasket, but you have to pressureize the system and get where you can get a good view of the leak. Because this could also be an intake gasket or a freeze plug as well.

As far as the miss, not likely that it would be related to an external coolant leak. However I would pull the plugs near the leak and check them for antifreeze burn. And check compression there as well.

If the head gasket is leaking to repair you have to remove the head, when you do this check for white valves. This is a sign of anti burn. This could be a crack in the head which will cause a missfire.

Good luck billymac