Does your brand of oil turn dark and look dirty and how fast does it?

Been running Shell Rotella 15-40. Doesn't look bad after 5K miles. A little darker that when put in. Nothing like my old 8.1 gasser. Stuff used to turn black in no time.

i been runnin rotella and its black as night after 500 miles. i was mainly wondering if the synthetic stuff did the same.

I just changed my oil saturday. Took out mobil-1 5w-40 synthetic truck and suv, and it didnt look black at all with 4k on it. Replaced it with amsoil.

Shell Rotella syn 5w-40 turns dark slowly, as if in a gasoline powered car.

I run rotella 15w40 and the oil is usually a light shade of black when drained, on 5k intervals.

Dan

The dark color is soot which is a normal byproduct of combustion in diesel engines.

i been runnin rotella and its black as night after 500 miles. i was mainly wondering if the synthetic stuff did the same.
Do you have an EGR equipped Duramax?

nope just an old lb7

According to what I've researched, precision 37 is completely correct. It's normal for diesel engine oil to turn black relatively quickly because it's suspending soot--and that's a good thing.