Posted: May 02 2009 at 12:44pm | IP Logged

98 XE 4WD-Pacesetter headers, Gibson Catback, K&N filter, Billstein, Michelin Just rolled over to 100,000 miles.

Royal Purple 5w30-3000, change filter, 6000, change filter, 9000, change oil & filter Filter=K&N gold

Trans & diffs=Royal Purple 75/90 Transfer case= Royal Purple Synchromesh

24mpg at 55 wo the ac on.

Posted: May 06 2009 at 6:50am | IP Logged

What's important to remember is that all oil does is lubricate and suspend dirt enough to carry it to the filter.

The difference from synthetic oils and conventional oils is the synthetic oils supposedly don't break down to water and sludge under high heat and pressure as quickly.  This is why synthetic oils claim to go 10,000 miles or more.  The real question is how clogged is the filter getting over that many miles?

Personally, I just use conventional oil (Castrol GTX) and a good quality oil filter every 3000 or 4000 miles.  An oil change is cheap and takes 45 minutes at most (including the clean up and all), so it's good insurance!

A few people have cut open a number of oil filters to see which are the best.  Basically, Mobil 1 is the best, but you pay the extra!  After that, Purolator, K&N, and Wix are more or less the same build quality.  Don't touch any Fram filter with a 10 foot pole!  The internals are made with cardboard instead of metal, the check valve leaks, and the filter media on some of them contain Teflon, which can be harmful to your engine.

A good last tip is change your oil with the same oil every time.  Different oils have different chemicals in them (some oil comes from PA, some from overseas, etc.), and all the seals and gaskets in your engine tend to adapt these.  I've heard switching oil brands often can cause gasket leaks in the long run.