Strange question

[ATCZERO]

Does oil turn black sooner in a diesel engine as opposed to a gas engine? If so why? My diesel seems to turn black in just a few hours after an oil change. It only has 300 hours on it and I use Mobil1.

[topsites]

To answer the question, yes it does, to my understanding almost as soon as it is changed.

I could not tell you why because I'm not a diesel type of guy, but it does do it and is considered normal.

[Charles]

Ya I thought the quickie oil change guy was ripping me off for awhile there:laugh: Takes a good many running hours for the diesel tractor oil to turn black

[White Gardens]

Depending on the motor it will turn black fairly quickly.

The black comes from the soot that enters the crankcase from blow-by. Newer diesels aren't as bad but most older deisels will turn the oil black in a matter of seconds.

You could do an engine flush but it wouldn't matter as it would still turn it black quickly from all the residue.

If you change your own oil, some suggest adding tranny fluid to the motor and let it run for 10-15 minutes before changing the oil. The tranny fluid helps to break up any large deposits.