Car Maintenance | DontKnowCars.com

Common engine repairs include disassembling, replacing or repairing, and reinstalling primary parts such as pistons, connecting rods, crankshaft, camshaft, valves, and related parts. Unfortunately, modern engines require precise parts and assembly so most consumers don’t repair engine components. Depending on what’s needed, it may be less work to buy a new, rebuilt, or used engine and replace the old one. In many cases, that’s what professional mechanics do. (The photo shows components of a typical engine, including a cutaway of two cylinders.)

What could go wrong with an engine that would require major repair?

• If the engine lacks power, the valves or piston rings could be worn.

• If the engine uses excessive oil, the piston rings or valve guides could be worn. (Note: first check underneath the car to see if there’s an easy-to-fix leak.)

• If the engine makes a light clicking noise, the valves may require repair. (Note: first check to make sure that all spark plug wires are working properly.)

• If the engine will start, but won’t run, the timing chain may be loose or broken.

• If the engine makes a sharp metallic knock when running, the cause could be the bearings at either end of the connecting rods.