2005 Kenworth Tractor Trailer

          We are going to take a bit more time to explain some basics with this report as it’s the first one showing in the vehicle list.  This report contains 3 consecutive samples taken from the same oil over its entire drain period of 104,000 kms in this engine.  You always read samples horizontally, across the page.  The oil used was AMSOIL’s AME 15W-40 Heavy Duty Diesel & Marine Oil.  Items of interest/concern are colour coded, with no colour being the best.  Some people get concerned when they see a bit of colour on their reports, but some colour is to be expected.  If the majors are lit up with orange or red, then get concerned. 

There are two characteristics of your oil you want to know about for sure: its viscosity and its TBN.  An oil's viscosity is one of its most important attributes.  One of the hallmarks of a quality oil is that it will maintain a stable viscosity across a long lifespan & drastically varying service conditions.  That is exactly what you get with AMSOIL products and what you see with this oil here.  Many cheaper oils thicken or thin out significantly with severe service and/or extended drains, sometimes way outside of their stated viscosity ranges.  This really compromises their ability to protect.  AMSOIL is as good as it gets and you see that reflected in the stable viscosity figures here throughout the 104,000 kms of service this oil saw.  You will also see that confirmed in the other oil reports here and in the white papers and comparisons found on the Performance Tests and Literature page.  

An oils TBN, or “total base number,” is also very important.  This measures an oils reserve alkalinity and its ability to neutralize acids that develop in engine oil as a natural by-product of the combustion process.  TBN is also a general indicator of oil life remaining, assuming no other issues are at hand.  This particular oil starts with a TBN of 12 when new, which is very high compared to other oils.  When the TBN dips below four Oil Analyzers will begin to flag it with green, and by the time it’s at two it needs changing for sure.  When the TBN sinks below two or even one and lower the "total acid number" (TAN) begins rising rapidly.  This causes the oil to become more and more acidic, dirty and congealed (among other things).  At this point its degradation will accelerate exponentially.  If not serviced very quickly it will cause increasing amounts of accelerated wear and damage and will eventually snowball into full blown engine failure.  This is even more likely to happen if you use chlorinated oil additives.  (See Aftermarket Additives.) 

At the first sample this oil had 35,000 kms on it, and was in excellent shape with very little engine wear going on.  So the owner of the truck kept the oil in for longer and had it sampled a second time at 66,000 kms.   Once again the oil was very good.  There was very little engine wear and the lab said it was suitable for continued use.  So he kept the same oil in all the way up to 104,000 kms when it was sampled a third time.  As you can see, there was still very little engine wear and the lab said yet again the oil was suitable for continued use!  The sheet is almost completely white.  There is no way anymore to know for sure how far it could have gone, but based on the rate of oil degradation my estimate is he could have gotten another 15-20,000 kms out of this oil safely, possibly more. 

          This engine burned a bit of oil even before he switched to AMSOIL, so that continued through.  There are two sides to this.  With poor ring seal the oil would have been contaminated by a lot of combustion by-products as they blew past the rings into the sump.  This speeds up the contamination and decay of any oil, even though AMSOIL’s lubricants are better able to deal with this because of their premium additive packages.  However, since levels were freshened up periodically with new oil we have something of a draw in terms of contamination.  In general though, new and tight engines are always easier on oil because it stays cleaner.  If this engine didn’t burn any oil at all, these reports would have been even more impressive. 

         This owner-operator is smart and uses a fairly good by-pass filtration system, which helps.  He also uses AMSOIL’s diesel concentrate, which is a multipurpose fuel additive.  It helps keep the rings and top-end a little cleaner, improves mileage a bit, and also helps fight acidification of the oil, all of which would have helped the oil last a bit longer.  All told, this oil was still in decent shape and cleared for continued use even after 104,000 kms of continual use.  This is impressive.  

          The owner used to do oil changes every 15 to 20,000 kms with standard petroleum oil before this, so by going to AMSOIL and keeping the oil in for over 100,000 kms he avoided having to purchase over 200 extra liters of standard oil on this one drain!  He saved a lot of money, down-time and waste oil, in addition to saving some fuel, plus AMSOIL did an excellent job protecting his engine.  Over-the-road trucks with tight, healthy engines can get even longer drain periods using this oil.  You can trust the quality and expertise of AMSOIL!