[Almasp]

I got a used 2006 Colorado with 250K on it, and it burns oil at a confusing rate. When I first got it I did a compression test and all 5 cylinders were cranking around >195 psi.

I topped it off at 254980k and when I checked last night at 255480k it had burned through over 1.5 quarts.

With my very limited understanding, I don’t see how I could be burning this much oil with a compression over 195! I’m hoping for some wisdom on this issue.

 

[esmth]

early atlas' had valve guide wear issues. You could also have a plugged/non-op pcv orifice which could cause excessive oil consumption. At idle, if you remove the oil cap, does a noticeable bit of blow-by come out? You could try the cap test, just place the cap upside down on it's spot and ideally you want it to be sucked down, or barely jiggle in place.

 

[mike66]

Worn valve guides and or bad valve stem oil seals,or pcv system clogged can cause substantial oil consumption! All of these conditions is possible on a high mileage motor!

 

[Almasp]

Thanks I’ll try that simple test today, I shouldve mentioned that my PCV orifice was clogged and a tiny bit of oil had been blowing out into the resonator box, but not much it seems. Also in the past two weeks since monitoring my oil level, it hasnt gotten clogged again.

I’m not sure how much of a difference it makes for the valve guides but I don’t smoke on startup, just lots of soot around the exhaust.

If I discover there’s a decent amount of blowby, then how could my compression be reading so good?