Join Date: Dec 2008
Location: Tyler, TX
Thanked 407 Times in 347 Posts
Your mechanic is correct. Every diesel will blacken fresh oil in a few hundred miles, if not sooner. This takes a little longer on newer engines as they run cleaner, but it is simply the "nature of the beast".
Cleaning the crank-case is a temporary thing, the soot from combustion is carried in the oil, so no matter how clean you make it, in a few hundred miles the oil has a fresh load of black soot.
This soot is no problem at normal levels, and the oil is engineered to handle it.
'93 F-250 HD, 7.3L IDI, 5spd - FARM TRUCK
I Support: Trailer brakes an every axle over the towing vehicle's GVW; CDLs for RVers; Safety inspections for ALL vehicles and 6 axle trucks (97K GVW proposal).
Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote - Benjamin Franklin
I vote for LIBERTY!