We have an oil leak

[General Stalin]

Bumping this as I've been having an oil leak in my 2007 Yukon Denali. I noticed drops under my oil pan a while back and it got progressively worse so a couple weeks ago I replaced my oil pan gasket and drain plug. Now I'm getting no drops at all but STILL going through a ton of oil. Just went on road trip (about 900 miles roundtrip) and ended up putting two whole quarts in it by the end... still not a drop on the ground. I am collecting some oil on the little metal cap on the bottom of the bellhousing, but I popped it off and checked rear main and it's dry as a bone.

Possible oil is running down the side(s) of the bellhousing from the back of the topside of the motor? Valve cover gaskets or sending unit issue? There are no drops on the ground which I just don't understand, unless it only leaks when it's running and/or it's burning it all inside the engine.

 

[Nashoba]

My daughter has a 2007 Suburban with the 5.3 liter and it uses oil prodigiously (with gusto). It has about 165,000 on the clock and has been using oil since about 30,000. They bought it new. They are not good on maintenance, generally speaking, but keep a fine eye on the oil consumption. I have read much about the 2007 5.3 liter engine and most of it is bad. Chevy is loathe or loath (I never can remember how to spell it) to repair them and denied there was a problem with them for quite some time. I have even seen a thread or two on this site and others about that engine specifically. Bad deal. My personal opinion is that your engine is flawed inside and is consuming oil, not leaking it. I think there is a fix, but it is expensive. Last time my daughter was down here, I bought her 12 quarts of Castrol GTX High Mileage 5W-30 Synthetic Blend motor oil for her to carry in her Sub. I also got a couple of quarts to keep here in the garage for an "emergency" oil fill should she need one. The Sub runs fine and gets OK mileage, but it drinks the oil!

 

[General Stalin]

My truck has the 6.2 and right now it seems to be going through oil at a rate far beyond reason. Like I said I had to put 2 quarts in it over the course of 900 miles. Thats insane.

Engine runs like a clock besides that.

 

[Nashoba]

At 88,976 miles, our, 2008 Tahoe Hybrid threw a check engine light and shut down. The engine is a 6.0L. The codes indicated low oil pressure at the time. The mechanic at the dealership reset the code and started the engine and it showed 40-60 pounds of oil pressure. He took the pressure sensor out and installed a mechanical one and the oil pressure was 4 pounds. After all was said and done, they installed an "Engine Valve Rocker Arm Manifold", a "Manifold to Cylinder Head Gasket Kit", and an "Engine Oil Pressure/Temperature, Fuel Pump Pressure Sensor". This manifold and the gasket set reside beneath the intake manifold in the valley between the heads. There was some talk from the service manager that there may have been an instance of low oil that caused this. Have you ever had the check engine light come on and the vehicle engine stop running?

 

[General Stalin]

Not at all. Only thing I've had is an engine oil low error. At first I thought it might be the oil level sensor screwing up but I checked my dipstick and sure enough there was no oil on it.

 

[Nashoba]

Have you run a compression test to see if there is any oil being sucked up from the crank case? Any coke build up in the tail pipe?

 

[General Stalin]

Haven't gone that far in diagnosing. Was hoping more to see tell-tail signs of where else it could be coming from and just replace part(s) gaskets as needed. If it isn't burning it off but actually leaking out from somewhere then it seems that it may be a real PITA to find - possible somewhere on the back of the motor where I really can't see without taking the top end apart. You think a compression test would be the next logical check?

 

[Nashoba]

I am pretty bad about going under my vehicle while the mechanic is changing the oil and filter and doing a grease job. Also, I have a good enough relationship with them that they will come get me to show me something that needs addressing if they see anything during the process. When you are under the vehicle with them, it is easy for the to show you what they find. I have dealt with the same dealership, quick lube site and private mechanic for many years, so they know how curious I am and work with me because they want my repeat business.

You might look at the top of the cross member under the engine to see if there is any grimy oily buildup. That is a very obvious place for drips to fall and not hit the garage floor.

 

[General Stalin]

Yeah I don't work with any mechanics I do all my own wrenching and do it on my back in the driveway with the truck in ramps/jacks. I'll have to jack it back up and get a real good look under there again but where the crossmember is there should be oil on the bottom of the pan and/or oil filter that is above it but they are dry.

 

[Nashoba]

You aren't 70 are you? Used to do all my own wrenching, too, till I had both hips replaced and a bunch of other crap that comes with old age, including arthritis. It sucks.