I'm hoping to tap into the experience of our members. I have had a problem with my van (6.2 NA) smoking for a few years and it has been getting progressively worse. Here are some of the symptoms:
- Blue/light gray smoke coming from the exhaust pipes, especially under load
- Oil droplets on the body above the exhaust pipe tips and black sooty dots on the back doors (I believe from the exhaust)
- Burnt oil smell and oil in the intake manifold (appears to be coming through the crankcase depression regulator (CDR))
- I have some minor oil leaks, but I end up adding approximately a quart of oil every 1000-1500 miles. I believe the volume of the leaks are less than the volume that I add.
- Approximately 250,000 miles
- Coolant level does not drop

I think it is conclusive that I am burning oil (if you think there is a chance that there is another issue, please let me know.) I ran a check on the CDR, which met the testing specs perfectly. I replaced it anyhow and it made no difference in the smoke coming from the exhaust or oil droplets on the body. I did a compression test, here are the results:

1 - 382
2 - 370
3 - 370
4 - 402
5 - 379
6 - 380
7 - 382
8 - 402

I am out of spec (should be 380-400 each cylinder). I don't have enough experience to know if this type of result is bad enough to lead to the oil consumption that I am encountering. I'm guessing some people here can comment...

I am relatively certain that I have a fair amount of oil coming through the CDR, as evidenced by the oily and burnt-oil-smelling intake manifold. I am thinking that I may have a large amount of blow by, which ends up as a large volume of oily air coming through the CDR and back into the cylinder.

I guess I am trying to figure out with certainty the cause of the oil burning. I am guessing it is worn rings/cylinders. I'd like to avoid a rebuild, especially if the rings/cylinders are not the issue. I am hoping that there could be another cause. Valve seals? Any advice or comments would be appreciated. Thank you!