Using oil between changes

[2xtreme]

Well I am now back in possession of my H3 . The dealer is running an oil consumption diagnosis, after 1500 mi I am to take it back in for a check. If there is no oil used in the 1st 1500 mi I am to return it at 3000 mi. Document ID # 1271371 2006 Hummer H3 states " Excessive oil consumption (not due to leaks) is the use of 0.95L (1.0qts) or more of engine oil within 2,414 kilometers (1,500 miles)

[f5fstop]

And if you look the oil pan has a seal on it (or should have) and the dipstick is also sealed (again, should be).

[2xtreme]

This may be a silly question but if it is more than a quart low at the 1st check than what?

[f5fstop]

Then they have to diagnose the question, "why is it using oil." This is normally followed by a compression and leak down test. Compression test will tell the condition of the cylinder head gasket, valves and cylinder rings. A leak down test will show what is specifically wrong in a cylinder if it fails a compression test. They apply high pressure to the cylinder via the spark plug hole, and where the air leaks out determines where the problem is.
If all are ok, then they have to look for a leak. Very seldom, but aluminum castings can be porous, allowing oil to leak out the pores of the aluminum. This usually shows oil streaks on the external engine surfaces.
In the early days of aluminum engines, this was not unusual. In the modern process, especially lost foam, it is unusual, but can happen.

If rings are bad, they will rebuild the engine, if valves are bad, they will replace the head, if gaskets are bad, they will replace a gasket. If the engine block is porous, they will usually replace the short block of the engine (engine block, pistons, crank, etc. but not the cylinder head). All depends on how they are servicing the engine.

[2xtreme]

Thanks for all the info, I will keep you updated when I find out more.

[2xtreme]

Well I am back with some info as to why my engine was using oil between changes. My dealer performed an oil consumption test, I was instructed to put on 1,500 mi then return to the dealer for a check. I was 2qts low again I was set up in a loaner H3 and was told I would be called back tomorrow. The tech called me back the following day as promised and told me that there is a service bulletin on the cam cover and the cam cover gasket. This is what was allowing the oil to be burned off, so if anyone notices any abnormal oil consumption this may be the reason. I will be monitoring the oil more closely and keep you guys informed of any more problems.

[f5fstop]

Good to know, but I can't find the bulletin; wonder if they are talking about a notification from technical assistance? I have to assume the dealer added flourescent dye to the oil when they did the oil change, this should have located the oil leak with a black light. (Just talking to myself.)

Hope this fixes the problem.