An engine assembly typically refers to the combination of components that make up the engine in a vehicle. This includes the engine block and all of its internal parts, as well as some of the accessories that are bolted to the engine, like the cylinder heads, intake manifold, water pump, exhaust manifold, and the like.
It is common for a technician to make repairs to an engine and its components. The pistons, crankshaft, valves, camshafts, and other parts can all be replaced and by a qualified technician. But sometimes an engine is better off being replaced as an assembly, whether because it is so severely damaged or because it is more economical to do so. Precisely which components are included in the term “engine assembly” can differ somewhat by vehicle manufacturer or retail supplier of an engine.
Engine assembly replacement is a difficult and lengthy process. It requires special tools, techniques, and experience. The procedure to replace an engine in most modern vehicles necessitates that the vehicle be safely lifted and supported in the air for access to a number of components. It also requires that several systems be disassembled or removed. For instance, the cooling system must be drained. The AC system must be evacuated. The suspension system must be at least partially disassembled. The transmission or transaxle must be removed.
The process for removing and replacing an engine generally involves the following (abbreviated) steps: