maxnix wrote:"The use of a synthetic oil may allow oil drain intervals to be extended. In a clean, dry system, a synthetic oil may allow for extended drain periods (double or triple the drain interval of a mineral oil is possible) if the mineral oil was being changed due to oxidation. If the oil drain interval for the system (with mineral oil in use) was set due to external contamination entering the oil, then the use of a synthetic oil will not allow the drain period to be extended. Oil monitoring by laboratory analysis is the key to understanding the situation."
Dennis is almost always right. Well at least 99.99%
What external contamination? I don't think they are talking about the average trace dust amounts. If that's the case, then Mobil and all the other mfg's that guarantee thier product for up to 15k, etc. will be buying lots of engines. In both cases where I sent Amsoil in for analysis, there was no sludge or dirt in the oil, and both cases (1st sample with ~12k, 2nd w/ ~ 8k) oil passed all tests and was suitable for continued use.
People either believe, or they don't, but I have seen the light