The 2001 F-150 I just bought has 91000 miles on it. The previous owner used synthetic oil. Should I just keep using the synthetic or would it not hurt to switch back to conventional?

I have never used synthetic before, so I got on the Internet and did a bunch of reading and even being more expensive, the synthetic seems to be the way to go.

I am up in the air.

 

i've used syn in everything i've ever had. nothing but good luck!

 

DO you have to continue to use synthetic oil? NO you can switch to whatever oil you prefer. But I would recommend staying with synthetic or a blended oil.

 

If it has been synthetic, stick with it IMO.

 

Just use the dealership $25 oil changes.

It includes a Motorcraft filter (better than Fram) and 5W-20 synthetic blend, which is known to be a very good oil for the price.

Change every 3,500 miles. It's still cheaper than using full synthetic even if you change every 5,000 - 7,500 miles.