you can’t rebuild it… i just went through the same thing. bad news is that you have to buy a new block and rebuild IF your crank is any good. My monies went to a reman, then there’s the core charge, if you go with a reman, usually 800$, in which you may have to cough up becuase they can’t reuse your block. I was able to talk down my core to 400$. weigh the costs to replace or re-power. ETEC has my next$. that’s my 2cents