Using oil...

[Meatbag]

...about 1 gallon every 5k miles. Also have some blow-by coming from the oil filler tube and dipstick. Not sure what would be considered significant blow-by but it seems like it's more than it should be. Carbon packing? Any way to clear that up without taking it apart (can't afford that right now)? CM871 in a 2010 Prostar at 770k miles.

[Meatbag]

I should also add that the oil pressure slowly drops during that same duration of time and then when I change the oil and filter it comes back to normal (36-38psi).

[Meatbag]

I should also add that I am running a lot more wide-open miles now compared to the last three years when I was doing mostly local work. Could this possibly be built up carbon deposits coming loose and clogging the filters?

[Signature620]

CM871 breathing heavily and plugging oil filters are both signs of broken rings. Have the blowby checked by somebody with the right equipment and make sure it's checked with the air compressor both pumping, and then unloaded to rule that out as the problem.

[bwake]

Worn seals inside the turbo can also cause excessive crankcase pressure. If you are going to try and determine the root cause of this issue yourself, along with checking the pressure with the compressor on (pumping) and off, take the time to check the turbo out as well. This can be done in a couple different ways, 1. A smoke machine attached to it (compressor side) will allow the smoke into the crankcase if the seals are going bad or, 2. Pull the turbo oil drain line and place it in a bucket and see if there are bubbles coming out, if so, that is the pressure coming from the compressor side finding its way into the crankcase.