2006 5.3L oil leak

Anthony Owner New York Posted   Latest   Edited  
Unsolved
Propulsion
2006 Chevrolet Suburban 1500 5.3L (T LM7) 4-spd (4L60-E)
Oil Leak

So all of our local engine/machine shops have retired. No one left to call. ¼ million mile Suburban 5.3l, actually a clean truck. We replaced the oil pick up tube o-ring due to low oil pressure and engine noise. Not bad to do and the 2nd one I've done. Both came out good but this one looks like it developed a rear main leak. Now we are not an engine shop nor do we disassemble and analyze engines. 

My question could we have built too much oil pressure for a 290K rear main? Also could the pcv/engine crankcase vent system be frozen? Euro vehicles have replaceable vent valve/cyclone valves etc that plug up freeze up and cause all kinds of check engine lights and oil leak problems. I looked into replacing the crankcase vent system on a 6.0l LS and I think it is part of the intake plenum. thx in advance!

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Scott Technician
Florida
Scott
   

Typically it’s not even the rear main, it’s the rear engine plate gasket. It gets brittle and cracks, and there’s your leak all in all, it’s not a bad job, we usually can knock one out In a half day i don’t think by replacing the o ring on the oil pump is the root cause, in my opinion, it was not leaking as bad with low pressure. i believe that engine heat, caused by excessive idling cooks…

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Jesse Owner/Technician
Pennsylvania
Jesse
 

Hi, I am not sure about the plate that scott is refering to , but one place I would usaully do is the gasket at the oil cooler connection , but those did not look like a rear seal, whats the chance that the pan gasket is seeping?

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Matt Technician
Texas
Matt
 

He is talking about the plate that houses the rear main seal. The plate is bolted to the back of the block, you can buy the rear main kit from felpro that includes the gasket. I agree on the oil cooler lines or block off, common leak.

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Elias Owner/Technician
California
Elias
 

I dont think its from the oil pressure. It could be the oil pan, but if you sure its not then replace the rear cover assembly with rear main seal. Napa sells one that I have never had a return with. Part number is noe 6005648.

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Tyler Technician
Kansas
Tyler
 

I agree with replacing the rear main as a plate assembly. It's really not a terrible job. As far as the PCV system, you could check crankcase pressure while idling and 2500 RPM with a manometer or vacuum gauge on the dipstick tube. With respect to you and your techs, but are you sure the two long bolts at the rear of the oil pan were torqued correctly? It's easy to overtorque them and strip…

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Glenn Owner/Technician
Texas
Glenn
 

Hi Anthony, Let's keep it simple and work from there. Locate the oil pressure sender on the top back of the engine and check for leaking. Many of these had the tall oil sender unit and they were common to fail.

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Cody Diagnostician
Illinois
Cody
 

If it actually is the rear main seal, could low oil pressure have caused some excessive main bearing wear? Maybe allowing the crank to move a little more. Just my 2 cents

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Jarrod Technician
Michigan
Jarrod
 

To verify a rear main seal on these trucks. You can get a decent view of the rear main seal by pulling the round inspection cover on the trans bell housing. With the engine running look up there with a flashlight you can see right through the flexplate.

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David Owner/Technician
Alberta
David
 

Anthony, I am thinking the oil pan re-installation has disturbed the rear main seal housing when put back together. Or, the pan is not back on properly.

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