98 Grand Prix GT 3800 V6 Oil leak

fritcr · 04-04-2008, 08:13 AM

I just (finally) got me a GP GT. I love it! BUT it leaks oil all over the place. I can't really tell where it is coming from. I changed the oil and it has leaked out about 1/2 quart in 200 miles. It runs perfect and has 113k on it. I can't see where the oil is coming from...almost seems to be coming from the frontish to oil filter area. Is there something in there that might be leaking alot. It leaks all over my garage floor. I saw something about the oil filter adapter gasket but can't really tell if that is it or not. Also...if it is...is that hard to change. I'm pretty mechanicly inclinded and do most light repairs myself. I just put a front wheel bearing hub on it. It might be the pan gasket but it seems to be more concentrated around the lower front of the engine. It is not the valve cover gaskets or the intake. Something below that.
Thanks for any advice!
Rob

BNaylor · 04-04-2008, 09:33 AM

The most common sources of leaking on a SII 3800 engine are the oil pan gasket and rear main seal. Have you jacked it up for a closer inspection with proper lighting to see if you can find the source? 1/2 qt in 200 miles is excessive.

richtazz · 04-04-2008, 11:24 AM

I agree with bnaylor as to the most common leak areas. With the volume of oil you're losing, if it was a rear main, the oil would most likely be on the drivers side, not passenger side. Rear main leaks can follow the oil pan rail and end up dripping on the passenger side, but not at the volume of oil you're losing. I would more thoroughly inspect the oil pan gasket, as the piece between the timing cover and oil pan end is a common failure point, which is right where you describe your leak is. If that area is clean, then I would say it's the oil filter adapter leaking.

To answer that question, the oil filter adapter is located on the back side of the engine (firewall side), passenger side of the car. It has 3 bolts, and is not difficult to change, but kinda hard to access.

fritcr · 04-04-2008, 02:30 PM

It is not the rear main for sure. It is coming from the front of the engine..(pass side) I will try to get a better look this weekend. Clean it up and then let it run and see if I can tell. It is driping off the back pan gasket bolts alot so I wonder if it is the pan but it could be just running down and dripping off of them. The oil spot is mostly on the pass side firewall side. I heard the pan gasket is expensive to fix. OUCH! Can I do the adapter gasket myself?
Rob

BNaylor · 04-04-2008, 03:13 PM

The best thing to do is use engine degreaser and then take it to a self service car wash and use the high pressure spray wand to clean all the crud and old oil away first. Then jack it up or get it on a lift. There will be alot of dirt and old oil accumulation. Also located at the rear of the engine passenger side is the oil pressure sending unit so check to make sure that is tight or not the source of the leak.

The accumulation of oil seen on the back pan bolts is typically the signs of a bad pan gasket. Another thing you can do is double check the tightness of all pan bolts less the ones towards the timing chain cover since those are hard to get at. Make sure they are not loose. Use an inch-lb torque wrench and make sure they are at least 89 in-lbs and then give it just a slight extra turn after you hear the torque wrench click off if using a clicking torque wrench. Also, there are the pans bolts driver's side that you will not see until you remove the plastic inspection cover on the bottom of the bellhousing next to the starter. Also, with that cover removed you can see if there is any oil dripping from the rear main seal just to be sure.

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