Does anybody know if the 6.0L Vortec is known to consume oil on the H2? I've been looking through the internet but couldn't find any answers only for the H3.

 

One of the many GM Truck and SUV forums will give you a lot more results. The HD trucks and many of the full size SUV's use the exact same engine.

It is essentially the same as the 5.3 engine as well (just different heads and pistons).

My 1999 GMC Sierra has the 5.3 and it is low miles, I've had it since 2002. It drinks oil. Literally a quart every 500 miles. It does not leak and it does not smoke. Has always been like that.

My 2003 H2 has the 6.0 (again, essentially the exact same engine). It does not use hardly a single drop of oil. 6000 miles and its still dead on the full mark.

 

I'm in agreement with MixManSC, I have had many H2s (2003-2007) with mileage ranging from 10k miles to 186k miles and none of them consumed any oil that was noticeable on the dip stick. If you are seeing oil consumption I would assume there is a problem somewhere.

 

Thank you guys for the information. I really appreciate it!

 

A LOT of things can also cause heavy oil consumption. Frequent aggressive driving, a lot of towing, in addition to internal engine causes like worn rings, out of round pistons, warped heads, bad valve seats, worn valve stem seals, etc. Could be any number of things and realistically as much as a quart used every 2000 miles can even be considered normal, more if a vehicle is frequently used under certain conditions like heavy towing and very aggressive driving.

I'm not sure why the 5.3 in my GMC uses so much (it is essentially the same engine as the 6.0 in my H2) while my H2 uses none at all. Truck does not smoke, does not leak on my driveway or anything. It does have a very minor (and somewhat common) leak at the rear main seal but not enough to even drip on the ground so I know that is not using a quart every 500 miles. I've tried a number of things but one I'm about to do is change it up to 10w40 oil and am going to go ahead and replace the rear main seal in the next few weeks.

 

Mixman does your GMC have AFM? I had a 2010 Tahoe that was in great shape and it would consume oil, once I turned of the AFM it pretty much stopped that, I know we don't have the AFM on our H2's but it might be worth a reprogram on your GMC if you have the AFM. I now have a 2012 Tahoe and I turned mine off with a handheld superchips device. It drives much better now.

 

I wish that was it..... mine is the very first year of the newer engines. Its a 1999 with the 5.3. They did have a TSB about the PCV valve and consumption and I changed that to the updated fixed orifice style. I also added a Moroso catch can which does stop a LOT of nasty crud from going into the intake but not nearly enough to account for the oil losses.