Another Engine Oil Leak Question

jeff5295 · August 11, 2009

I've searched many posts and applied all relevant repairs that I've heard of, but still have an oil leak. I'm hoping someone else may have some experience with the same problem.

2001 Denali XL 6.0L w/ 164,000 miles. Engine oil leak.

Filter area wet, exterior of bell housing wet, starter bolts wet.

I pulled inspection plug on bell housing and there does not seem to be any oil inside. To me this says the RMS is OK.

Replaced oil cooler block gasket, no decrease in leak.

Replaced oil pan gasket, maybe a minor decrease in leak.

There does not seem to be any wet oil residue above the oil pan on either side of engine, so I'm ruling out the CPS o-ring. It does not appear to be leaking.

If I hadn't just replaced the pan gasket, I'd swear it was leaking. I cleaned the gasket surface on the block and pan. There did not seem to be any issues with either surface. The old gasket did not appear to be that bad either. I used a fel-pro gasket and I don't believe it should have required sealer, but now I'm wondering if I should take it apart again and put some RTV on it.

Is there anything else I could be missing before I drop the front differential and pan again?

CapitalTruck · August 12, 2009

Man, that sounds frustrating as hell. Are you seeing any spots on the floor or noticing your oil level drop? My 04 seems to leak a little bit from god knows where and it shows up in the same area you're describing. However, I've never noticed a low oil level or anything like that so I haven't fooled with it.

jeff5295 · August 12, 2009

Man, that sounds frustrating as hell. Are you seeing any spots on the floor or noticing your oil level drop? My 04 seems to leak a little bit from god knows where and it shows up in the same area you're describing. However, I've never noticed a low oil level or anything like that so I haven't fooled with it.

It's like having the Exxon Valdez parked in the driveway! There's oil stains every where it's parked and the oil level goes down pretty quick. It doesn't seem as bad with the new pan gasket, but it's only been about a week. I used to go through close to two quarts between oil changes. We park it in the garage during the winter and I had to put a catch pan under it because it was leaving such a mess on the floor and it was running into the floor drain.

I need to put it up on the hoist again, now that it's been run for a while. Maybe I can get a better idea of where the leak is actually coming from.

Has anyone replaced a pan gasket in one of these motors? Is sealer generally required? The manual said to put it on the corners, which didn't make sense since it is a one-piece gasket. I'm thinking the wording in the manual was carried over from the old style 4 piece pan gaskets. It actually appears that it is leaking more from the middle of the pan rail and running back anyway.

Pretty frustrating to say the least. I had to drop the front differential to replace bearings so I waited to do the pan gasket at the same time. I'm not looking forward to dropping the diff again to get access to the pan, but if that's what it takes to fix this leak, I don't have many other choices.

Anyone have suggestions?

SilveradoWV · August 12, 2009

I use Red RTV Silicone on just about every gasket...

REV353 · August 12, 2009

get a bottle of oil dye and put it in. Run to wal-mart and get a black lite bulb and put it in your shop lite, wait until it gets darker outside and start looking. The only problem I have run into is if you are needing to drive it and the wind blows the dyed oil around. I always keep a bottle of the oil and coolant dye in my shop. As far as silicone, Threebond makes a 1104 and 1187, this is the same stuff we use to put motorcycle and snowmobile engine case half's together when there is no gasket to use. I apply this to the surface your going to put the gasket on, let it sit for a bit and keep pressing the gasket on and the Threebond will hold the gasket in place and seal up any imperfections, you can use this on both surfaces the gasket seals. If there is a seem in the block or rubber seal or a separation in the gasket (oil pan) I either use RTV black or the "right stuff" to seal the spots, you must be 150% sure there is no oil on any surfaces or the silicone will not do it's job.

Hope this helps.