My understanding is that it's OK to burn new or old motor oil as long as you don't have a "Cat". I think this was discussed in a past issue of TDR. Some over the road Cummins powered trucks have oil tanks and use a system that adds clean oil to the crankcase while burning some of the used oil. I believe they go many thousands of miles without actually changing the oil. I read about this system on the Cummins website last year.
------------------
Ron
'96 Club Cab 2500 4x4, 4:10LS, Camper/Tow package, Auto, BD Pressure Loc, Mystery Switch, TST 230/605, Cat under "Test", Cummins Chrome, Mag-Hytec rear and trans covers, Boost, Pyro and trans gauges, Optima Red Tops, All black. Tow 14k HitchHiker triple glide 5th Wheel. Also use 9. 5' Lance camper. NRA Life Member.