I have a 2004 F250 that I use to pull a fifth-wheel in the summer. Since I live only a couple miles from work I only drive my truck on the weekend. That only amounts to about 8000 miles a year. Yesterday I changed my oil at the 3000 mile mark. But with 6 months since my last change. Is this too long to wait? Should I change it every four months even if I only have 2,000 miles on it? That seems like a waste of oil but I have heard that oil loses its effectiveness over time.

Thanks
Randy

 

6 mos is fine. just every week or two take it out for a longer highway drive, >20-30 mi. and get the engine warm enough to keep moisture out and you could make it to 9 mos to a year on decent oil, maybe longer. Your towing in the summer accomplishes that for those months.
Preferably CI-4+ rated over CJ unless you are assured of running ULSD all the time.

 

Go with the severe duty service interval. As stated drive it once a week for 15+ miles on the open road.