I have a 03 HO. I would like to hear from someone that has either done this or is a cummins mechanic. I am gonna have my block bored cause the cyl walls are messed up. My question is how far can I go before I have to worry bout overheating and such? Or should I just bore it and sleeve it? I will be doing some towing. I have a juice w/att, intake, exhaust, flux 1.3 injectors. Thanks for any help.

 

Overheating will not be a problem. On the 5.9 I would not bore further than 1mm, that is according to Cummins specs. How bad are the bores?

I have done a few If you have any questions, shoot me a PM or give me a call.

 

I thought mine was gonna need a bore after the number 6 piston had an arguement w/ the cylinder. Turned out a hone fixed it right up. Fortunately 90% of the "damage" was just aluminum from the piston etched into the cyl. wall