I manage a large fleet of mostly Yale forktrucks running the 2.0L Mazda engine. We run the snot out of these things and it's not uncommon to get 30K hours out of a truck before I retire it. I've actually got a couple at 40K hours.

Anyway, the 2.0 has proven to be incredibly reliable, but I've had to get some head work done on a couple of them.

When reinstalling the head the manufacturer's recommendation is to replace the bolts. I don't understand why though. They are not torque to yield type. As long as they pass visual inspection, I see no reason not to reuse.

Last truck we did head work to had over 20K hours and we re-used the bolts. That truck was headed towards retirement, so I wasn't going to spend any more than I needed to spend.

Now I've got a truck with 11K hrs that just had excessive carbon/tar build-up on the valves and in the combustion chamber, so we're going to freshen up the head. That truck is just middle aged in my world, so I don't want to skimp, but I still can't seem to justify new head bolts.

Any thoughts or experience on the subject?