I had all 8 motorcraft injectors put in like 3 months ago. I was wondering is there any kind of oil or fuel additive that I should use every so often to help keep them healthy?

 

I run Motorcraft SAE 5W-40 Full Synthetic Diesel Motor Oil with no additional oil additives, and Motorcraft PM-23-A in the winter & Motorcraft PM-22-A in the summer for the fuel. Good Luck, Russ

 

Injector health needs adequate fuel pressure and FICM voltage too.
Monitor them.

 

I'm in the same boat as you. Just had all 8 replaced. #2 was totally shot and a bunch of others were in various degrees out of spec so just bit the bullet and replaced them all. Repeating what the shop I use said, I don't really care what fuel additive you use just use one with every fill up. I use the one the shop has bottled with their own sticker on it because they usually throw one in for free, but used to use Motorcraft Cetane booster. Pretty cheap insurance in addition to the FICM and fuel pressure operating as they should.

 

There was a study done by the Southwest research lab (See second link) if i remember correctly and one of the best things you could do for fuel lubricity in run a blend of as little as 3% commercially produced bio-diesel. Also ash-less 2-stroke oil performed better than some name brand additives.......
Here is a link but it is not exactly what i was looking for.: Fuel Additive Test - Ultra-Low Sulfur Diesel - Diesel Power Magazine
Found it :https://www.catamaransite.com/refere...ubricity_test/
Long read but well worth the time.....