Help with ISX 15 CM 2250

[Rawze]

remove the oil and drop the oil pan and let it sit over night with 20 psi on the coolant system,.. look for coolant seeping out of the bottom of the cylinder liners next day while turning engine by hand slowly. Find out what cylinder it is.

Cummins injector cups are not meant to be replaceable. By the time you get a leaky cup, the rest of the head is almost always slap worn out any ways. - trying to fix injector cup is a stop-gap measure at best.

LASTLY -- YOUR
TAKING IT TO STEALERSH%IT!!! -- THE WORST PLACE YOU CAN POSSIBLY GO unless you just WANT to be ripped off in return for blind guessing, half-arssed incompetent work, and an empty wallet.