After 2 month in the shop repairing a broken pulley bolt, new rings, engines bearings, new oil and water pump, now my engine (3.5 l) make a sound like a diesel engine, the mechanic said the hydraulic lifters need to adjust them self, and i need to buy a hydraulic lifter additive.
Is that right or is something wrong in my engine?

 

I highly recommed you try this before any further action:

Mitsubishi Tech - Minute Mod: The 5 Minute Lifter Noise Fix

This cured my diesel knocking issue and is also listed in the factory service manual.

Good luck!