[THEFERMANATOR]

Originally Posted by macojoe

I have been using wally world oil for years!! Even now with a 2004 Yamaha HDPI, never a issue! If you are under warranty use what they say, but all bets off after warranty is gone!

I would NOT use wally world oil in a HPDI unless you want to have a costly engine repair. HPDI engines have a MUCH different oil requirement, and improper oil is what lead to the majority of early FICHT failures as well as MANY optimax engine and compressor failures.