guitarfish

I have been fighting with my son's 97 GP 3800 (130K miles) for a couple weeks now tracking down coolant leaks.

Trouble began when the serpentine pulley broke off. My son drove 15 min back home with the engine temp hovering around the red area on the gauge, which, as I emphatically told him afterward, was a VERY BIG MISTAKE. Let the coolant leaks begin...

First I replaced the water pump, because there was coolant all over it. Still losing coolant, and seeing it collect at the WP, and it turns out the plastic heater bypass elbow was leaking. Replaced that. It was severely deteriorated on each end.

Well, that was 2 days ago, and still losing coolant. Then tonight I found it - coolant appears to be leaking from the upper intake manifold gasket, driver's side, firewall side of engine.

No indication of any coolant in the oil, and no visible steam in exhaust.

Assuming the UIM gasket is the only problem, I'm looking for an estimate of hours to do the replacement. I've done things like wheel bearings, WP, PS pump, valve cover gaskets...but never any internal engine work.

Quite unhappy about this...

threewest

gm has had alot of problems with intake gaskets leaking coolant..very common..i did mine on a 2002 so im not sure what a shop would charge...i paid 80 for the gasket set itself...i know book time for labor is about 7 hours of labor...i did it in five its not that hard just a little time consuming...just make sure you dont over torque the manifold or you will have the same problem....

guitarfish

Thanks threewest. I'm not planning to take it to a shop, it's gonna have to be DIY. Looking at the plenum, it doesn't seem like it would take 5-7 hours to do just the UIM...but maybe there's more to it.

threewest

i was talking about the gasket between the head and the intake...if you have coolant coming out of the upper plenum gasket that sits on the intake then you most likely are getting coolant in the combustion chamber...the upper plenum only takes about 30 minutes to take off...

gersandy2000

I had a recall by GM for a 2001 Grand Prix, to change the bolts on the intake manifold due to expansion when they heated up and would cause the manifold to leak. So you might want to check on this.

guitarfish

Well it's been a long week folks. Two days ago I tore down the top of the engine, replaced both upper & lower intake gaskets, and put a new plenum on too. For what it's worth, there was no damage to the old plenum.

The original owner of the car had all recalls done (only 1 I think). I have a 98 and an 02 GP and never had a recall for manifold bolts, so I'll have to look into that.

The old gaskets were definitely faulty. We'll see how it goes now with this work done.

__________________
Current Grand Prix's
2008 GP - 65,000
2002 GT - 197,000

Former Grand Prix's
1994 GP SE - Flipped at 231,000
1997 GP GT - Traded at 134,000
1998 GP GT - Traded at 225,000