I've also used a broomstick, a wood dowel rod, or a piece cut off a discarded garden hose as a field expedient stethoscope as a noise locating device. Don't forget to check the fuel pump- - - - -I've seen a couple of engines rebuilt because of a knocking noise from a noisy pump.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!