2004 GMC G3500 Cargo Van

            This analysis report is pretty impressive considering how long the oil was in the engine.  It’s also instructive of the importance of staying on top of your filter changes.  This was the first time this gentleman ran AMSOIL in his van, using both our premium oil & filter.  Because the van had about 170,000 kms (106,250 miles) when first switched to AMSOIL, it was automatically considered a severe service application.  This owner was using our premium oil filter and our older “SSO” premium 0W-30 oil, which AMSOIL guaranteed for one year/28,000 km in severe service conditions.  He went a bit past the life rating for oil before getting it tested at 33, 377 kms.  We don’t recommend this, esp. with older equipment, but it did save him six regular oil and filter changes and turned out okay after all. 

            This oil could have been changed a little sooner.  The silicon count, which is elevated to 30 ppm, reveals there is grit in the oil...the normal dust that is ingested through the air filter.  These results make me wonder how well the air filter was doing it's job at this point.  Air filters that don't do their job let grit pass directly through the top end.  If that were the case then even a new oil filter would not have prevented much of the minor wear in this report, because ingested dust will first do it’s damage to the rings and bore before any can be filtered out by the oil filter.  

AMSOIL doesn’t use Moly in its oils, although other brands do.  Because AMSOIL doesn’t use Moly any amount in the oil is flagged as anomalous.  What is seen here is likely a residual amount left over from the previous oil.  The level is low at only 17 parts per million and is a non-issue.  Thankfully wear levels were quite low.  Don’t forget, this oil was in this engine for over 33,000 kms.  This makes the levels appear high relative to oils changed out every 6000 kms.  However, the rate of wear is very low here: many cheaper oils would show this kind of engine wear after only one third of the km's driven.  This analysis demonstrates very good wear protection is going on.  

This oil was in there for a long time and the TBN number was getting low, but not so low as to be unusable...according to the lab it was still suitable for continued use even at this point.  The extra contaminants in the oil near the end of this drain period would also have degraded the TBN.  If the air and oil filters were changed halfway through this drain period, for example (if the owner knew he was going to use the oil for so long), the TBN would have been higher and wear metals even lower at this point, and it would have been suitable for even longer use than recommended here.  Overall this oil did very well protecting the engine, especially considering how long it was in service.  No other oil or oil filter could have done this well over such a long period of time.