I've been losing 1qt/700 miles for a few months now. The oil usage is strange because the level will be fairly constant for ~700 miles then suddenly drop a quart. No smoke out of the exhaust. Engine is not covered in oil, nor are there any drips on my garage floor. I've tried different grades, dino, syn. They all do it.
Power is great. Smooth accel on partial and full throttle. I can log but not sure what to check that will tell me where my oil is going. Knock signal maybe?
I have two catch cans now to help. The PCV line separator is basically dry. The breather line separator has only a quarter teaspoon of condensation/oil after 700 miles.
GST did a compression/leak down test last week and said everything was good. Cylinders 1 and 3 had 5% leak down. Cylinder had 4%. But cylinder 2 had 10%. This would seem a bit high, although Mike assured me that this is acceptable and it not likely to be the cause of my oil loss.
Because of the satisfactory compression/leakdown I decided to swap the turbo. I was trying to eliminate bad oil seals in the turbo. It's not the turbo.
This last time it dropped, I drew a sample and sent it off to Blackstone to determine if the shearing, fuel, etc. Still waiting for the results.
Today, I'm getting some help from the guys at GST to hunt down the source of the oil loss.
- 1qt/700 miles
- Good power and idle
- No smoke
- No drips on the garage floor
- Nothing significant in either catch can
- GST did a leakdown Cyl 1=5%, 3=5%, 4=7%, 2=10%
- GST did compression "good" (no numbers were recorded)
- Replaced the turbo
- Waiting on Blackstone result to rule out/in shearing or fuel dilution
- GST will pull the header to inspect it and the valves
- Headers were dry
- Exhaust valves look OK
Any thoughts, ideas, comments are encouraged.