I am upgrading my RV to a 2005 Country Coach Inspire with a 400 HP 8.8L Cat C9 engine that takes 9.25 gallons of oil per oil change. I live in Seattle and typically drive the RV about 5,000 miles a year, mostly here in our very temperate, but wet, climate.
I asked for an oil recommendation from the local Cat dealer and they suggest conventional 15W40 API: CJ-4 changing it every 10K or 6 months. This makes oil changes a significant expense at twice per year.
My diesel repair shop charges $6 per quart for conventional, but will install Rotella T6, if I provide it. Since Walmart sells T6 for $22 per gallon that makes it cheaper than conventional oil for me. Still that is $220 of oil plus a filter per change.
I have always been confused about the time limitations on oil changes. Oil isn't like milk - its doesn't have an expiration date on the bottle. What causes the additives in the oil to wear out or dissipate so quickly just sitting in my oil pan without the engine running much?
Wouldn't regular 6 month or 12 month oil analysis be a better, and cheaper, way to figure out when to change my oil? Assuming that I got an extra 6 months between oil changes it would be cheaper as well.
In Seattle, it rarely gets to the single digits in the winters, and we usually only have 5-10 days in the 90s in the summers. 100 miles east it is much more extreme. Wouldn't T6 (5W40 API: CJ-4) be better for my engine than the 15W40 that Cat and Cummings like to recommend for engines this size?
Answers to the questions in bold would be appreciated.
I asked for an oil recommendation from the local Cat dealer and they suggest conventional 15W40 API: CJ-4 changing it every 10K or 6 months. This makes oil changes a significant expense at twice per year.
My diesel repair shop charges $6 per quart for conventional, but will install Rotella T6, if I provide it. Since Walmart sells T6 for $22 per gallon that makes it cheaper than conventional oil for me. Still that is $220 of oil plus a filter per change.
I have always been confused about the time limitations on oil changes. Oil isn't like milk - its doesn't have an expiration date on the bottle. What causes the additives in the oil to wear out or dissipate so quickly just sitting in my oil pan without the engine running much?
Wouldn't regular 6 month or 12 month oil analysis be a better, and cheaper, way to figure out when to change my oil? Assuming that I got an extra 6 months between oil changes it would be cheaper as well.
In Seattle, it rarely gets to the single digits in the winters, and we usually only have 5-10 days in the 90s in the summers. 100 miles east it is much more extreme. Wouldn't T6 (5W40 API: CJ-4) be better for my engine than the 15W40 that Cat and Cummings like to recommend for engines this size?
Answers to the questions in bold would be appreciated.