Ohayden, I run Mobil 1 in my 1 ton Furd van, with a 7.3 engine. The 1st owner used Mobil 1 so I've continued with it. I can make a round to Phoenix and back (about 3300 miles) and not use but a quart. This engine has 221K on it.
One doesn't have to use a syn oil to keep an engine clean. Harvard (of Evansville, Wi.) makes a one micron bypass oil filter that will actually clean your oil. That is, it will remove contamanits faster than they accumilate. This filter works fine with either type oil. I ran 186K on the same oil in a Cummins NTA 420. When I'd pull the tappet covers to run the overhead it was clean as a pin. I blew an oil cooler or I wouldn't have changed oil then. I have kpersonally know an engine that ran 360K on the same oil. In a trade magazine a few weeks ago I read of a fleet manager (Schneider National, I think) that had ran trucks on the same oil that many miles also. They used another brand of bypass filter with a natural oil. I started using these filters two decades ago. Slowly they are begining to catch on. Mike
