Started this one so as not to be a thread stealer.

A co-worker and I were discussing different types of oil recently, and he told me that since I have been using regular oil since the truck was new, it would be useless to switch to synthetic now. He based this on the truck having 21,000 miles and if there was damage caused, due to friction and what not, synthetic would pointless.
My counter was that if no damage has occured, synthetic could only ensure everything continues to run smoothly. Right? Thoughts please?

 

Synthetic can be useful regardless of the mileage. I had a 93 Dakota that had 120K+ and after I started using synthetic oil, the mpg's did improve a little and the engine ran a little better.

 

Your co-worker is an idiot. Maybe not an idiot (but maybe so) but definantly uninformed. Your truck came with a synthetic blend in it from the factory.

 

I figured his theory far fetched. Just wanted to get some different opinions. Thank you much.