Mechanics

GRANDPRIX HEADGASKET PROBLEM?

1998 Pontiac Grand Prix • 6 cylinder FWD Automatic • 130,000 miles

Car: 1998 Pontiac Grandprix
Engine: 3800 V6 L36 N/A

Problem: I was driving normally as I pulled up to a stoplight, engine already at normal running temperature.
As I came to a stop I noticed the car was idling rougher than normal. I drove another half mile through town and the service engine light came on as I pulled into a fuel station, engine running extremely rough.
As I came to a stop next to the fuel pump the car was shaking so much it felt like I was riding a wooden roller coaster flying down a gravel road littered with potholes.
I turned the car off, popped the hood up and everything seemed normal except for a strong smell of antifreeze burning. Engine wasn't hot and there was no smoke to be seen.
I decided on trying to start the car to see if the problem persisted.
The engine turned over about half way and stopped just as if the battery was dead, but I knew the battery wasn't dead.
I waited for about 20 minutes and tried to start it again, and this time the engine started but was running extremely rough as it was before, so I turned it off again and just called AAA and had it towed home.
By the time it got home it had been several hours so I tried turning it on again seeing as the engine was cooled off.
The car started as it normally does and idled smooth as ever. After a minute or 2 white smoke was barreling out of the exhaust, but the car was still idling smooth. Gave it a few more minutes and the rough idling began.

Its been a while since this happened and it still starts and runs normally until it gets warm so im thinking its a blown head gasket, but im not sure.

what do yall think?
Avatar
Mii777
March 21, 2011.



A very common problem on this 3.8 is for upper plenum(black plastic intake plenum) to go bad and dump antifreeze into the cylinders, causing the engine to smoke badly and actually hydrolock the engine, this is where I would start.

PROTECH1980
Mar 21, 2011.