alongside all the fluid changes, you should keep a check of the T belt for stretching and adjusting the pump timing (with a dial gauge i.e.) check the valve clearances periodically and adjust with different shims accordingly..
give your injection pump a cleanup treatment, (liqui moly or lucas) whatever rocks your boat.. (check your injector spray pattern if you hear pounding or consistent marbly knocking at revs)
Do replace your T-belt at about 100,000 Kms and its coolant too (never use plain water in a diesel, the shocking/rattling effect of the diesel combustion cycle foams the coolant and cavitates the block and coolant pump too.