3.4L DOHC blown head gasket repair walk through

[mantrucker72]

Anybody out there got a complete walk through on a head gasket repair on the 3.4L DOHC? I Just blew mine on my 94 Olds Cutlass Supreme got chocolate milk all over my oil dipstick. And the same result when i change the oil.

[jmgtp]

I just replaced the heads on mine. I don't know of a walkthrough but it is a pretty straightforward job. I didn't encounter any real surprises. A manual would help, the official GM stuff shows up on eBay once in a while otherwise something like a Haynes should be good enough.

I can give you torque specs, tightening sequences, etc if you need them. Or if you have other specific questions just ask.

[crazyd]

Pull the motor and do both. Trust me on this, if one's gone the other's about to go too. Just did mine, $16.99/ea at Autozone. You can reuse the head bolts, FSM does not say they must be replaced (though it does say if you pull a head you have to replace its gasket).

[jmgtp]

From my experience, I'm going to disagree with two of your points.

I don't understand why you would want to pull the motor to do the rear bank? The motor in the car doesn't impede the job. I think it would take longer to pull the motor and replace the gaskets rather than just replacing the gaskets motor in car.

Also, the head bolts are torque to yield and *should* be replaced after each use since they are designed to stretch. I know I don't have the spec or means to measure with such accuracy to determine if a headbolt can be reused. It is about $60 to replace the headbolts on both banks and good insurance.

Points I will agree on: headgaskets are cheap! Only $17 per bank for FelPro at AZ. And, yes, might as well do both rather than have the other one fail on you down the road.

[crazyd]

The factory manual does not state that the head bolts must be replaced.

It is more work to remove, reinstall, torque the bolts properly, then reinstall the cam tower on the rear head with the engine in the car than out, but it certainly can be done if you don't have the facilities for an engine removal.

[RedZMonte]

Yeald to torque bolts must be replaced... if its stated or not they will strech and you don't want to reuse them..

You can pull the motor or do it in the car. everyone i have had expeience with on the DOHC's leave the motor in, but if you wanna pull it it might be a good time to replace other possible leaks... ALLWAYS replace the "Dist. O-Ring" while the rear head is off.. prevenative maintenence.

S

[crazyd]

All the information I have on this says that the head bolts do not need to be replaced. I have confirmed this with the 1992 Pontiac Grand Prix factory service manual and with Fel-Pro. If someone can show me where it states in an authoritative source that the head bolts for the DOHC must be replaced I would appreciate it. This seems to be either a myth or a marketing line.

[crazyd]

Yeald to torque bolts must be replaced... if its stated or not they will strech and you don't want to reuse them..

All critical fasteners in the DOHC are torque-to-angle. They do not have to be torqued to their yield strength.

[55trucker]

Not to hi-jack mantrucker's original thread, but the topic of *Torque-to-Yield* bolts comes back to using alloy heads on iron blocks. The alloy heats up at a different rate than the iron block and moves on the gasket. These bolts are needed for these purposes because of their elastic properties. That is why once used they are not to be used again as the elastic qualities have been lost once pulled off the engine. You cannot re-torque them and expect them to have the same strength they originally had. I do hope that you don't have any problems with your heads crazyd, but I'm reluctant to hold my breath and wait.

[pocket-rocket]

I've reused mine because I was in a pinch for cash and haven't had anything happen from it, even running to 7,100 RPMs at the drag strip. But, knowing what I know, if I had to do it again and I had the cash, I would replace the head bolts and use a Fel-Pro head gasket set to replace every gasket in the top end, and do the dist. o ring like Shane said. To do the dist. o ring right on this engine, the only way to do it is when the rear head is off, so take the time to do it now for sure.