Loosing oil

[blazzinbird]

So as the title says our 08 Denali is loosing oil. The bell housing has oil on it, but I dont think the rear main is leaking.
Reason being, now I will blame the Chevy dealer. Apparently a few oil changes ago they didn't put the oil cap on right it was just sitting on it, not making a perfect seal. During this oil change when I popped the hood to check the oil level. To my surprise I was perfect level. I put the cap on correctly, and week later the level dropped some.

So is it possible that pressure building up in the crankcase forcing oil out?

 

[Derick]

/losing

 

[Big Mama]

Yes the oil is under pressure and like all fluids looks for any way out. How much oil are you loosing?

 

[blazzinbird]

About a quart a month rough guess
So I know if it had a PCV valve it could need replaced.

 

[ivin74]

Put a clear fuel filter on the pcv line that goes to the manifold if it turns black you know the oil is going into the manifold and its being burnt if not you have an oil leak some where.

 

[mooman]

Check oil cooler lines if you have them. Qhere the oil cooler enters the block, for some reason, gm decided to put a metal plate as a gasket. It usually leaks around there. Also, check underneath to see if there are any apparent leaking around. Top side around valve covers and oil cooler lines.

 

[SnowDrifter]

What have you checked / ruled out so far?

 

[Kraig]

Bell housing is wet where—top, all around, or bottom? Just one side or both?

 

[dnt1010]

How many miles you got on this 2008? (average is 15k per year so I would guess 165,000?) Obviously this is a year model that had the bad design drivers side valve covers so it was probably changed out years ago? Now here is what I found with my 2009. The updated drivers side valve cover was on mine but it was covered with sludge and not functioning. For 60 bucks I bought a new one and put it on in less than an hour. Oil consumption is much better now. 3000 miles per quart used versus 1000 miles. It does make a difference. Plus if you do have a small rea seal leak if the PCV system is not functioning corectly it could make that problem much worse by pressurizing the crankcase forcing oil out anywhere it can squeeze out. Up through the piston rings etc you get the picture............