Hey guys I have a 2007 hummer h3 that have roughly 119889 miles . One thing I noticed which is strange is that every once in a while I add oil . I don’t drive the car much but last oil change I made was with fully synthetic mobile one and filter too. And that was few month ago I checked yesterday and oil mark Was at half . I checked under the car around the oil pan and all and I don’t see any leak . Does it usually just eat oil ? Does anyone experiencing this ? And how to figure out where the oil go and stop it if that’s not normal ??

 

First thought is yes you're burning oil.

 

but if I am burning oil won’t be a smoke coming from the exhaust or smell like burned oil. I don’t smell anything and no smoke what so ever

 

blow by oil getting sucked into your PCV system and pooling in your intake but not enough has accumulated to get sucked back into the engine and burned yet?

 

Oil consumption over how many miles? If you lost a bit over 5,000 miles I would not be too concerned. If you lost 1/2 Qt in 1000 miles I would be and do some investigating.

 

def around 1k miles maybe little more . Where do I start to investigate ?

 

but in this case my intake would be kind oily and it’s not :/

 

what is the outlet pipe? The muffler must be clean and slightly corroded. but not black from soot. if it is in soot, then the engine consumes oil. and the fact that there is no smoke and smell, it is the catalyst that works. if the exhaust is clean, then check the valve cover gasket, especially at the rear. oil drips and blows away on the go. so no smudges but there is consumption. no more options.

 

Consider the oil you are using. I had the SAME issue. Sometimes for me it was as bad as 1 quart in 1500-2000 miles. I've got more miles than you, and I thought I would be rebuilding.

I was using Pennzoil platinum full synthetic high mileage oil. One oil change I couldn't find that oil, so I went with Pennzoil full synthetic high mileage (not the platinum). The oil loss went back to a more reasonable number for my miles (1/2 quart in 3000 miles).

Try changing oil types and see if that does anything.

 

A lot of highway (high speed) driving? I was losing ~1qt every 2,000 miles. It would go down fast if on the interstate. I never saw smoke out the tailpipe.

This last oil change I did two engine flushes then put in Liqui Moly LM2020. So far, it looks like oil consumption had dropped off a good bit, but still to early too be conclusive.