Can a camshaft cause your car to make a noise?

f you hear a lighter tapping noise from the upper half of the engine, shut the engine off and remove the valve covers. A camshaft is commonly used to operate poppet valves in a piston engine. A cylindrical rod is situated in the cylinder block or cylinder head that has oblong lobes or cams which push open the intake and exhaust valves. This force is applied on the valve directly or through an intermediate mechanism such as a rocker arm, lifter (cam follower) and push rods that are used to press against the valve for movement. Each valve utilizes a spring that will return the valve to its original position (closed) after the force is removed. If a valve spring has broken or a cam lobe is worn down it will cause the engine to create a tapping or clicking sound. To test for this condition, remove the ignition coil connector, ignition system or fuel pump fuse to disable power to the ignition or fuel system. Remove the valve covers to gain access to visually inspect the valve train. Have a helper crank the engine over while you watch the rocker arms or cam lobes, make sure they are all going up and down the same amount, if one or more lobes are traveling less than the others you might have a flattened cam lob and the camshaft needs to be replaced or a hydraulic lifter/follower (where applicable) that has collapsed and will need to be replaced. Also inspect the condition of the valve springs, use a flashlight and small mirror to aid in the inspection if needed. If a broken valve spring is discovered it will need to be replaced to correct the problem. And the final check, look at the height of the valve springs and retainers when in the closed position (pressure off) they should be exactly the same height. If one valve is higher or lower something is wrong with the cylinder head, valve or valve seat and needs to be repaired.

~ Mechanic