What does it cost to rebuild a semi truck engine?

It depends on the extent of the rebuild, and if any optional upgrades are chosen by the owner. At the time of a engine overhaul, it's much easier to install parts that might be nearly worn out or to upgrade to better parts. So, there are a lot of decisions to be made and they all affect the price of the job.

Also, an engine rebuild could take place with the engine IN the truck (called an "In Frame") or the engine could come out for the rebuild (an "Out Of Frame") If the engine stays in the truck, the "In Frame" might cost $16,000 to $20,000. An "Out Of Frame" rebuild might cost $35,000 or more.