HAVE 1991 GMC SIERRA 2500

change the PCV valve...this couldn't hurt and is only a couple of bucks...what this thing does is take the pressure off the crankcase oil-air so that the pressure has someplace to go~

What color is the smoke?

Is the oil level lower everytime you check it?...say 1 qt/week of more?

was there variation between cylinders (psi wise?)

Johng, we are willing and able to assist, but when you don't answer, it make it difficult ya know

it gives us an opportunity to catch up H25...always had a problem with those slide to access the coffee type cups...spill the coffee and forget to slide the opening...just don't have the co-ordination for one anymore~

He's probably changing out his PVC valve~....an easy job, as you know~

smoke is blue. between 15 and 160 every cylinder.

150 and 160

does not use much oil about a 1/4 qt every month

Okay, thing I had in mind was the valve guide seals, but you are a step ahead on that. 1/4 quart a month I would say no worries. It's 23 years old, that sort of thing is really just probably worn rings, but not so worn out to be concerned with because you have decent compression.

get something better.

only has 185000

good compression rings bad oil rings