So my 2007 Suburban 1500 LTZ 5.3 @ 207k miles has been leaking oil from the rear recently. It leaves quite a dripping mess with each use. I am not sure where the FULL oil level surface sits withing the engine so I am not sure if it leaks more when on the full notch rather then the low hatch mark on the stick. But regardless it always will leak so I am assuming its the seal itself that's worn and needs replacement which estimated at $1200 from a local shop. The main concern is that a 2nd shop claims that it will still leak cause of a worn shaft at 207k miles and an engine replacement would be best.

Please toss me your thoughts and experience on this mess. Thanks in advance!

Ron

 

Three things to consider; 1) Your PCV system may be freezing up causing excess crankcase pressure which can push oil out of the rear main seal. Clean out your PCV system and install a vented oil fill cap. GM part # 12589430.
2) There is a possibility of engine block porosity at the rear engine cover gasket area. This would require nearly the same procedure as rear main seal replacement. There is a procedure to repair the porosity.
3) There is a revised part number for the rear main seal. 12592195.

Now to answer your question. Assuming your vehicle is in good condition, my OPINION is yes, it is worth it.

 

How is the rust underneath? That's the real biggie especially in the north east salt zone eating away at the frame in the spare tire zone.

 

Scotty Kilmer swears by this: AT-205

 

I cant believe after 25 years, my rear engine oil seal hasn't ever leaked. I just think the GMT-400 series was better made then in many ways then later models. She's got an NP/NV-3500 5-speed stick-shift, and they rarely ever leak, Might be the synthetic oil.

 

actually not too bad for being in the north east. Nothing major as far as rust. And I have already done the AFM delete with new cam and computer flash at around 150k. Added a high flow oil pump @ approx 170k. Engine runs super strong and smooth!

 

Scotty looks drunk, lol. I have tried a similar product a few weeks ago with no good results "BLUE DEVIL pour n go rear engine sealer". Funny how the one Scotty is using is for ATF but he says to use it in the engine as well.

There is a GM bulletin out on the rear engine plate/casing gasket leaks, especially at the top where there is a high pressure oil port. I guess I won't know until the tranny gets pulled.

 

Scotty has said it works on engine oil seals. The man knows what he is talking about. That said he did say you'd likely have to add some at every oil change, as well. If I had a bad rear engine oil seal I'd see how long it goes, and if it leaked, add some more, unless the motor was gone south, then a rebuild..

 

what viscosity oil are you running In your engine. My R.M.S had leaked before I inherited the car from my father (car info in signature) and I found out he was running 0W-30 instead of 5W-30 in the summer down here in the south. I put 5W-30 back in, cleaned off as much oil as possible around the R.M.S to be able to see if it would still leak and it still leaks but it’s about a drop every 50 ish miles and I don’t notice a drop in oil level on the stick either.

 

running 10w-30 during the 0-40 degree North east winters.... 10w-40 during summer