The problem with synthetics is actually the fault of the previous oil...why, you ask?
Well, if a PCEO mineral oil was previously used, and did not protect properly, the seals can now be basically encased in varnish, thus causing them to dry out and no longer perform their one function in life. Now, when you switch to a synthetic oil that cleans away the old varnish, the seals are now being asked to function properly, but no longer can.
Anyways, if you've sticked to half-way decent drain intervals with that truck of yours, you'll have no problems switching over to a synthetic.
In regards to an oil choice, at least when talking about this particular engine, I'm a big fan of running a thicker than O.E. recommended viscosity. Several people have tried M1 15w-50 in these style engines and have been very, very impressed. Gives great protection, but also makes the engine much quieter and smoother. Don't be put off by the viscosity printed on the label...give it a try.
Wix filter will be absolutely fine unless you're doing a lot of heavy pulling or something (read - high rpm) whereas you'd want a high-flow filter such as a K&N.
[ April 28, 2004, 12:22 AM: Message edited by: Jelly ]
