Last April I had the lash valve adjustment done on my CAT C-9 at the CAT dealer in El Paso TX. Mileage was 40,000 (07 Beaver Contessa). During a conversation with the service manager he offered the following advice based on my RV driving and the amount of miles driven per year. He said I should change the oil every 12,000 miles and no more. The reason he gave was the oil does double duty. Not only is the engine lubricant under high pressure but then when it goes into the HUIE pump the pressure jumps to 5,000 lbs per square inch (I think I remembered that right). Then it goes somewhere else and the pressure is momentarily even higher.

CAT says once per year or 20,000 miles for this engine. OK all you mechanics, lets here your opinions. Is there any truth to this or is he after me for more frequent service intervals. He wasn't gonna get any money as I use Speedco for my oil changes but I am interested in your opinions.

Ken Sair 2007 Contessa

My experience is that once a year, regardless of mileage, is a common practice.

Just an opinion...... Caterpillar is very diligent with filter design, oil specs, maintenance intervals, and designing their motors for longevity. They develop the fluid change intervals from oil analysis, engine tear downs, and evaluating critical part wear rates and tolerances. We will probably never wear out an engine in a motorhome and these engines see relatively light duty compared to heavy commercial truck fleet use. Given that they create their service intervals from data from the truck fleet analysis it would seem unlikely that we have to shorten the change interval recommendations that are provided. I had read about a Cat C12 teardown at over a million miles of use and the engine still had wear that was within tolerances and they expected another 250k miles before any internal parts were needed to be replaced. I sold an 89 Beaver Contessa last year with about 100k miles on a Cat 3208 and it still did not use oil between changes at 20 years old.

As long as you did not have an overheat condition, some fluid contamination, or have excessive sitting with condensation issues between oil changes I think the Cat service intervals should be fine. You could pull a sample and have the analysis done to see what the oil conditionn is and go from there.

Regards Ed

Ken,

To be safe annual changing is recommende or mileage, which ever would occur first.  With that said, oil changes can be safely extended through oil analysis.  Oil analysis cost about $20.  The results can tell you if it's really time to change the oil.  Another benefit of analysis is that it can provide you with trends of problems to come.

Gil

Ken,
In my opinion, changing the oil in your Cat more often than Cat's recommendation is a waste of money.

Gerald

Thanks to all who responded. I do change the oil annually and the highest mileage was 16,000 so I am well within CAT specs. I also get an oil analysis at each oil change and all is well so far.
I just thought, he was being a little overcautious (or greedy), and you have confirmed what I originally thought.

Thanks again

Ken 2007 Contessa

Regarding an oil analysis:  where does a person go for an oil analysis??

Gary,
You local Caterpillar dealer or any large diesel truck service center should be able to perform an engine oil analysis for you.

Gerald

I send my oil samples to Blackstone Labs. The cost is $22.50/test and they will mail you the sampling kits. When my ISl blew with 19K miles, I had the test results to show not only that all maintainance was done, but that there had never been issues with the engine prior to self-destruction.