98 grand prix MAJOR PROBLEMS need help asap!!!

[nevadagrandprix]

ok i bought this grand prix about a year ago, had a small coolant leak but not bad. its a 1998 grand prix 3800 series 2 engine with 172,000 miles on it. about a week ago the car started going under 1000 rpm in idle and it started bumping like i had a flat when i accelerated from the stop. i brought it back to the house, looked at it, then i noticed white smoke from the rear of the engine. then i tried to start it again and it would not fire. it was trying to start, battery is good. i towed it illegally, had it diagnosed, said it was an "intermittent misfire." So i brought it in to a mechanic, they said the spark plugs were doused in oil and when he changed them and started the engine, the exhaust was leaking coolant and oil out the pipe. so i towed it home and for about 5 days now, have been taking apart this motor with a buddy of mine. i saw a thread that an LIM gasket may have been the problem. right when i took off the intake manifold, it was filled with cooked oil and the LIM gasket looked cooked. there was also coolant inside the engine where the crankshaft is. So now i took the front head off and the pistons have cooked oil on them. now we've been up trying to figure out how to roll the engine forward. we took of the 2 front mounts obviously and the rear bracket and the engine has play but i don't want to force it forward. i don't want to bring it in to a mechanic so WHAT DO I DO?????!!!!!! also if you have any information on these problems, please inform

[tblake]

Why do you need to roll the motor forward?

Since you have the front head off, pull the back one and install new head gaskets, LIM gaskets, and UIM gaskets. Also check and make sure your UIM isnt warped around the egr valve. These will warp from EGR heat and coolant will fill the combustion chambors of the motor.

Thats what I would do. Make sure you torque everything correctly when you put it back together.

[nevadagrandprix]

Having a difficult time removing the rear exhaust manifold. Service manual says to remove engine mounts and roll motor forward......is there an easier way?

[GTP Dad]

Rolling the engine forward is the easist way. It isn't hard to move just remove the dog bones and rock the car. The engine should roll forward and stay there.

[tblake]

why not remove the exhaust manifold with the head? Disconnect it from the crossover and the downpipe.

[nevadagrandprix]

well no matter now the engine is fubar. so replacing the motor but can i fit a 3800 series 2 supercharged in a regular 3800 series 2 GT?

[GTP Dad]

You can but it isn't worth the hassle. You will need the following to complete the installation. Axle Shafts from a GTP, PCM, Wiring Harness, fuel pump, you can use the transmission from the GT but the heavy duty tranny would be a better choice. The normally aspirated engine is easy to find and I would stick with that unless you have deep pockets.

[tblake]

Why is the 3800 junk?

[GTP Dad]

The 3800 isn't junk. The problem is that GM used substandard gaskets on the NA engine and that causes problems. Normally the upper intake gaskets cause the majority of the issues. Replacing the manifold gaskets before there are issues can eliminate these problems and the engine will last for many years. Actually the short block for the SC and the NA are the same. The upper end is where the differences reside between the two engines.

[BNaylor]

The OP's engine could be junk depending on any further internal engine damage. The coolant contamination plays hell with the camshaft, connecting rod and crankshaft bearings if not detected and resolved timely.

In most cases all you need to do without a major teardown is replace the damaged intake gaskets, drain the oil and install a new filter. Then add engine flush or an additive like Seafoam directly into the crankcase to help get rid of the coolant/water residue left. Then do another oil/filter change. Maybe use a top engine cleaner to get rid of any coolant or carbon on the pistons. And then cross your fingers.

Also, don't forget the N/A and SC engines SII 3800 engines have different pistons too. The N/A L36 has a higher compression ratio than the SC L67.