Trying to diagnose a top of the engine oil leak

[2K8Lade]

I've been trying to fix an oil leak on my 2008 Escalade. Looks like it's running down both side of the block and leaving a lot of oil on the ground.

I have already done an oil pan gasket due to replacing the oil pickup tube O ring, the oil cooler block off, and the oil pressure sending unit. The OPSU was not leaking but was bad. Valve cover gasket area is dry on both sides. Doesn't appear to be a main seal.

I used a mirror and it looks like the leak is coming from just under where the oil pressure sensor is. Is this the valley plate or what else could it be?

Thanks

 

[89Suburban]

Very could well be the valley plate, how many miles on it?

 

[2K8Lade]

Just rolled 200k.

 

[2K8Lade]

In case anyone stumbles on this, it looks like it was the valley plate. I was able to take some of the cover bolts out with my fingers! The gasket material was rock hard and the orings had to be chipped out of the grooves.

As a side note I found some cracked PCV boots so hopefully that helps the rough idle.

 

[89Suburban]

Check the rear crossover steam pipe block off gaskets too and do the oil pressure switch and screen while you are in there.

 

[89Suburban]

Maybe even that from crossover pipe too looks a bit rusty. Valve cover gaskets don't look all that well either. Good job man.

 

[wjburken]

In case anyone stumbles on this, it looks like it was the valley plate. I was able to take some of the cover bolts out with my fingers! The gasket material was rock hard and the orings had to be chipped out of the grooves.

As a side note I found some cracked PCV boots so hopefully that helps the rough idle.

There have been a number of posts here where the valley plate bolts are loose. Not sure if they had wrong torque specs at the factory or what.

 

[89Suburban]

There have been a number of posts here where the valley plate bolts are loose. Not sure if they had wrong torque specs at the factory or what.

IMO it's a combination of aging gasket surfaces, vibration, oil pressures in the VLOM unit and ports, solenoids etc. Maybe leaking VC gaskets speed that process up? Certainly stands out as an issue on these. Not only does it start leaking externally but internally as well. I had a very noticeable difference in smoothness and power with thee new VLOM installed.

 

[Fless]

Are those VC bolts something you'd use locktite on?

 

[2K8Lade]

The gaskets were in awful shape. Very hard and brittle. I'm guessing as they age they shrink and that reduces the tension on the bolts.

It has overheated once when a heater core hose broke off on the interstate so maybe that was a contributing factor.

 

[John H Daniel]

Following this as I have similar leaks. In my 2011 Denali w/ 192k miles.
Tried a suggestion I saw on Youtube; you can reach under the front of the IM and feel 2 of the VLOM bolts. Mine are loose, so makes the decision anyway to pull the IM and replace gaskets and oil pressure sensor, etc.

 

[Maximus05Escalade]

I've been trying to fix an oil leak on my 2008 Escalade. Looks like it's running down both side of the block and leaving a lot of oil on the ground.

I have already done an oil pan gasket due to replacing the oil pickup tube O ring, the oil cooler block off, and the oil pressure sending unit. The OPSU was not leaking but was bad. Valve cover gasket area is dry on both sides. Doesn't appear to be a main seal.

I used a mirror and it looks like the leak is coming from just under where the oil pressure sensor is. Is this the valley plate or what else could it be?

Thanks

For sure could be valley pan gasket. do the knock sensors and harness while your there. Valve cover gaskets and intake gaskets too.

 

[Fless]

The knock sensors on the NNBS aren't on the VLOM.