So today when I got to work, I gassed it a bit in the parking spot to pull in (plowed snow pile blocking part of spot). Turned the engine off, went into work...Came out to go to lunch, start it up and a large size cloud of smoke comes out (enough to cloud 2 additional parking spaces, smells like burnt oil, not coolant. I let it warm-up, smoke goes away. I drive to lunch and now everything is back to normal. Never has there been ANY smoke output, which is my cause for concern. Could it be by gassing it, that some oil was transferred via the breather tube from the valve cover and drawn into the intake....that's my guess. Only reason I would figure this could happen is with too much oil. Oil was changed 4K ago, with 6 new quarts. What gives?

 

What year is your H3? Early 06 models had a valve seat problem due to head casting I believe. G.M. got the problem fixed and replaced alot of engine heads early on. Just keep a eye out and if you get anymore problems contact your Hummer dealer and let them know...

 

It's an early build 06' with 73,000 on it. Not sure if the head was ever replaced or not (bought it used), no codes were thrown, and I sure hope it's not the notorious "head problem" I've read about. I am definitely out of warranty. I'll see if it smokes again this evening when I head home.

Any other thoughts anyone?

 

this happened to me in my 93 pontiac grand am when I did a neutral drop. Maybe there is a correlation, maybe not?

 

So since yesterday, there hasn't been any smoke on start ups. I still find it extremely weird and an odd fluke. I'm pretty positive at this point that oil came up into the intake tube from the breather tube that attaches to the valve cover. My guess is a substantial amount of oil would have to be output by the breather tube, to drain all the way down to the combustion chambers. Does anyone know if a bad PCV valve could cause this? No codes were thrown, so I'm assuming everything is ok. I've heard of people running oil catch cans on the breather tube, but not sure why. Seems to be more for race cars.

Anyone familiar with PCV valves and their operations? Is it bad to allow oil to be drawn into the intake. I have the K&N FIPK installed.