[Dieselwrencher]

Nice Pete! 42k is pretty low miles. Luckily, I haven't worked on one of these for years. The biggest problem these used to have was the fuel pump drive module would always fail. The originally were mounted on the side of the injection pump. They would get hot, over heat and fail. The fix was to install a heat sink plate and relocate the module to another location to help keep it cool. Here is a good description of the mod.

https://www.dieselhub.com/maintenanc...elocation.html

I'm not sure which ones are the best to purchase these days. I can check into that. These are decent engines just don't expect a lot of power from them with a long life. I know guys, and have read online a lot about it, that turn the boost up or put a bigger turbo on them, and it's a matter of time before the magic smoke and parts come out.

You probably want to run a fuel system lubricant in it every few tanks of fuel to help keep the injection pump alive. These were designed when sulfer was still in the fuel and I know the ulsd doesn't help those injection pumps. I like to use stanadyne fuel system treatment. You can usually get it at local parts stores or it is available online.

https://www.google.com/search?q=stan...client=gws-wiz

On the harmonic balancer issue, I'm pretty sure you will have to remove the crank pulley and inspect the rubber to determine the condition. Otherwise if you feel/hear any vibrations or bird chirping sounds while it is running, it is probably okay. Usually front main seals leak and saturate the rubber which breaks it down and starts the separation.