using a GOOD filter is the key. the oil gets dirty, but not black... at 8500 miles my oil is dirty ('posed to be!) but not black. change the filter regularly, (2500-3000 miles) and you should have no problems. btw, amsoil's tech line says you can use synth in a brand new engine.my employer, an equipment rental/ lawn and garden center runs amsoil in ALL our equipment (gas and diesel) from day one. and as the mechanic, i see what these engines look like when they come in off rental.has anyone ever seen the air filter of an engine that has run 120 hours in an enclosed room full of concrete dust? not pretty! (perkins diesel on amsoil)
no the filter doesn't remove everything but the synthetic oil doesn't absorb as much of the dirt which is why you can run it longer. speaking of filters, if you are going to use a synthetic stay away from fram filters, hell stay away from fram anyway but especially if you are running synthetic and go for the longer oilc change interval. i prefer purolator personally or motorcraft. wix is good as well. when i change to the synthetic finally in this motor i may try one of those pure one filters
I'll be the first to admit I usually don't know my ass from my elbow on just about everything but it is my understanding that the filter removes the crud from the oil and that the reason for changing the oil every XX miles is because the oil has lost its viscosity and lubricity over time.
when i said use a GOOD filter, i wasnt going to say stay away from fram filters. but since the subject was brought up...i personally like wix, purolator, and motorcraft, also.I think the more blowby you have, the sooner your oil turns dark... if you think about it, metal shavings arent black, right? carbon is.if you pull an engine down that has, or is getting ready to spin a bearing, the oil looks like it has metalflake in it... it may not be black, but it usually has metal particles in it.i think im going to run the change of oil thats in the trusty ol' explorer 10000 miles, and send a sample off to amsoil, just for curiosities sake...ill keep everyone posted.