This was the biggest red flag to me in OP's description. It's also something I've seen in SO MANY ads for 6.5td-powered trucks. Seller always trying to make it seem like it's no big deal. If it's not a big deal, then YOU fix it and adjust the price accordingly. Nah. It's a big deal.
Richard
It’s a big deal. Basically the block is toast. Given the other issues the ‘94 6.5 faced and the cost of the improvements, it’s not worth purchasing.
I’ve got my ‘94 running nicely, but it took a new IP, new fuel tank, fuel lines and Raptor lift pump. Just a lot of work, but I did it myself. I also rebuilt the transfer case in the last year as the input seal was leaking.
I always tell people to not count on the 6.5 as your primary driver. If you want a 6.5, you need to own two so you have one running properly while you take the other one down to work on it. If you need it to get yourself to work on Monday, the 6.5 is not for you.
All that said, the 6.5 is the VW of V8 diesels: parts are cheap and it’s easy to work on.