I have a 1989 4x4 pickup that i dont drive much. I mostly use it for hunting and for taking off trash every now and then. I would say I only put about 2 or 3K miles on it a year. How often should I change the oil? I'm using Rotella T6 Synthetic.

 

oil breaks down after about 3-6 months. with synthetic you might be able to push the 6-9 month envelope depending how much the temperature changes in your area.

 

I'd think you could stretch it to once a year with good synthetic and 3K/Yr - but I've never gone more than a few months/8,000 Miles between synthetic oil changes...

 

I change the oil in my rockcrawler once a year. It probably only sees 500 miles a year on it.