Timming Belt replacement
The car has 164000 km and never winter driven (I live in Canada). It has a turbo. I have known individuals that have driven 25000km with the original timing belt and no problems. How necessary is to change the belt, tensioner and water pump.
If it's the original belt I would change it ASAP. The belt is 26 years old. It's probably dry rotted and about to give up the ghost. Miles don't matter if the original belt is that old. It needs replaced soon.
I would change all including the tensioner spring
If you need the PDF for that car let me know I have it mine is a turbo as well
Looking for a Used 300ZX in your area?
CarGurus has 143 nationwide 300ZX listings and the tools to find you a great deal.
Search Nissan 300ZX Questions
Nissan 300ZX Experts