A/C and odor

[lch0]

I have have an early 04 GMC D/A CC S/B 4x4 and have noticed a oder like that of burning oil after I have run the pickup for a while. I told the dealer to check it out and they say they can't find any evidence of any leaks that might be causing this. They also say they can't reproduce the problem, probably never got it warm. I also have a problem with the A/C getting cold. I also had the dealer check this out and they replaced a switch but that hasn't solved the problem. Has anyone else experienced problems like this? Also this is a California rig so could it be part of the EGR that's causing the stink. Other than that love the truck and it pulls our 12,000 Lb. 5th wheel with ease.

[Machine]

You have a crankcase vent tube located in the front of the truck on the pass side...it can produce that kind of smell.