Camshaft Repair: Signs, Causes and What to Expect

What the camshaft does

When fuel and air ignite in each cylinder, the pistons move up and down. The valves at the top of the cylinders must open and close at exactly the right moments to let air in and exhaust out. The camshaft makes that happen. Its lobes push on rocker arms or lifters, which open the valves, and valve springs close them again.

How camshafts are driven

Camshafts are driven by a belt, a chain or gears. Some engines place the camshaft low in the block, while overhead-cam engines place it above the cylinders, sometimes with a pair of camshafts. Some designs use computer controls to vary valve timing for different engine speeds.

Signs of a camshaft problem

• Backfiring, popping or tapping sounds from the top of the engine
• A dead miss or rough running
• Loss of engine power
• A check engine light
• Metal debris in the oil

What repair involves

A damaged camshaft is typically replaced rather than reworked, along with related parts such as lifters, followers or bearings when inspection shows they are worn. Because the engine’s timing depends on it, the repair needs careful measurement and assembly to the manufacturer’s specification. Regular oil changes on the schedule in your owner’s manual help protect the camshaft and valve train.

Have it checked

Ticking or misfires can have other causes, such as ignition problems or valve issues, so a diagnosis comes first. Our ASE-certified technicians can inspect your vehicle and explain your options. Book at whichever of our shops is most convenient.