Brother in Law wants to not get in financial trouble

dodge guy wrote:

That is wAy too long to go on an oil change that is running at 100% of its duty cycle! I always recommend a gas engine oil change every 3-4K miles. I always did 4K miles with mobil1 synthetic.

There's nothing wrong using the intervals the engine has been validated with.

I go as long as 15,000 miles. My 22,000 typical combined weight is pretty close to Class A territory. I do believe in annual at a minimum, and good oil is a must.