Oil leak, rear main seal ok? pics

[slowride]

So Ive got the nasty oil pan syndrome and Im trying to nail down the source of the leak. Read a post about looking thru the inspection hole to see if there was oil on the flywheel. Well I looked and there was what looked like something wet, it was a shiny spot that wouldnt photograph, up near the center of the flywheel. Doesnt appear to be leaking enough for me to think thats where my oil is coming from but thought Id post a couple pics to confirm. The brown colored areas on the flywheel toward the teeth appeared to be surface rust, it wouldnt rub off anyway.

 

[OR VietVet]

It would be best to put the year and engine in your signature so we know exactly what you are driving.

Rear main seal should, IMO, leave a trail from near the center of the flywheel downward. When you removed the inspection cover was there any oil on the inside area of it? Sometimes in an extreme instance you add dye to the oil and drive a day or two and then recheck with a blacklight. Before you would do that it is best, if you can, to use a spray oil cleaner and clean off as much as you can before you drive with the dye in it. These engines are known for oil cooler plate leaks, rear of intake and valve cover leaks. The oil gets blown around while driving. You could have an oil leak from any of them and an oil slow seepage from the rear main seal. Oil pan possible leak too.

 

[slowride]

OK sorry I forgot, its a 5.3 in a 2004. There wasnt any noticeable oil inside the bellhousing or on the cover I took off. Theres a little seepage from the valve covers but its only like 1/2 inch below the edges, nothing leaking down the back of the block. The oil cooler block off plate keeps a drop of oil on it so thats on the list to fix but theres also oil drops on the starter bolts so I was thinking its got to be coming from somewhere besides the oil cooler spot. Its got old oil stains around the rear edges of the oil pan but its not really wet there, its more wet at the rear sides where the bellhousing bolts up. I guess it could be migrating from the oil cooler mount, but all the way to the starter?

 

[OR VietVet]

I recently saw oil drops every now and then on the concrete. I had it at a shop and they allowed me under the rig in the air on a lift. The back of engine was dry. The valve covers were dry. the oil pan showed dry and the bell housing showed some wet and dry stains. The oil cooler block off plate was dripping ever so slightly. I replaced it with a new billet plate and a new gasket and new screws and I am now dry with no drips. The old plate was pot metal. I still have it and the old gasket and screws. Wind while driving blows all over under there. It isn't just what flows under but also what flows through the fan shroud and what hits the firewall and diverts down. You could fix that plate leak and still have seepage at the rear main seal that could get worse sooner or later.

 

[ks03]

Mine leaves drips. Figured the rear main was leaking. Ended up adding dye to rule out other leaks. Without dye mine looked pretty similar, with dye I could see my rear main clearly eclipsed all other leaks combined.

 

[BADRIDES]

My 2002 has had an oil pan gasket and the rear mail seal replaced and I have 212,000 miles.

 

[rockola1971]

Check and see if the oil pressure sending unit is wet or the area directly below and around where it screws into the block. Not uncommon for the sending unit to split at its seams and flow a good amount of oil out and down the back side of black and tranny bellhousing.

 

[cfore]

Slowride : I have the same problem with oil on starter bolts and I had my oil pan, rearmain seal, and valve cover gaskets replaced about 7000 miles ago. Mine is a 2003 Tahoe Z71 with the 5.3 and 201003 miles. Haven't found the problem yet.

 

[Larryjb]

Torque is critical for the pan bolts. You may wish to check those, especially the rear pan bolts.

Also at or on the back of the engine:

• Rear cover gasket (should have been replaced with the rear main, did they? There is a TSB regarding aluminum blocks, but I think your was before the aluminum block.)
• Valley gasket
• oil pressure sensor
• PCV
• camshaft sensor

 

[OR VietVet]

It has been suggested in other threads and I also suggested here in this thread. Get dye for the oil and follow directions to locate the oil leak.