what is engine overhaul

An engine overhaul is a process of deconstructing the current engine and having new internal pieces placed. It involves removing the engine from the vehicle and disassembling it. There are two types of overhauls: top overhaul and full overhaul. A top overhaul is when only the cylinder head is removed, leaving the engine block inside the vehicle. A full overhaul is when the whole engine is removed from the vehicle and stripped down. During an overhaul, the engine is cleaned, inspected, and repaired as necessary using factory service manual approved procedures. The procedure generally involves honing, new piston rings, bearings, gaskets, and oil seals. The engine may be overhauled to new limits or service limits, or a combination of the two using used parts, new original equipment manufacturer (OEM) parts, or new aftermarket parts. A top overhaul is less expensive than a full overhaul because the engine block is not removed from the vehicle. A full overhaul is more expensive because it requires more time and labor to complete.