Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

- General Information

There are four steps to diagnosing engine noise. You must determine the following conditions:
^ Type of noise.
^ Determine the exact operating condition under which the noise exists.
^ At what rate, and at what location in the engine.
^ Compare sounds in other engines to make sure you are not trying to correct a normal condition.

NOTE: Identify the type of noise. For example, a light rattle or low rumble. Remember, engine noises are generally synchronized to either engine speed (caused by the crankshaft, connecting rods or pistons) or one-half engine speed (valve train noise). Try to determine the rate at which the noise is occurring.