Weird intermittent noise from the front of the motor

[I6V8]

M20b25, 1989. Could this be the water pump bearing? I've had one go bad on me on an M62 but that didn't sound like that at all..

https://youtu.be/5bliLdELMSU?si=vHEyWkjlyT4GiqQG

I suspect the water pump because I recently might have slightly overtightened the alternator belt due to slippage, that's when this noise first started. It stops at times during idle then reappears. Timing belt has 30K on it, motor was completely rebuilt.

[82eye]

check your fan blades on spec ..

[I6V8]

Inspected the blades and they are OK. There's no play in the fan clutch or noises when I rotate the fan.

[82eye]

Inspected the blades and they are OK. There's no play in the fan clutch or noises when I rotate the fan.

you won't get it touching rotating by hand. the blades suck closer to the fan with higher rpm. happens quite commonly as the transmission and motor mounts age out, it allows the engine more forward play. creates a danger of the fan diving into the rad under hard braking.

other possibilities include the water pump and timing belt tensioner going out. you'd have to have an idea of the last time it was serviced. if it's getting close i'd do the whole kit replacement.

edit: you can remove the accessory belts off the car and start it to determine if the sound is coming from behind the timing cover. it'll be ok to run for a minute or two without the belts.

[I6V8]

You might be on the right track with the timing belt tensioner (bearing). Couldn't quite place it first but heard this noise on my M62 serpentine belt tensioner pulley 10 years ago.

It's definitely not the fan, I stopped that while the engine was idling.

The belt (Gates Racing) along with bearing and gasket on that motor has only 30K miles on it but this was 7 years ago and the tensioner might not have been replaced at the time.

Obviously, once I'm inside the timing case, might as well just swap out the water pump and belt to reset the clock.

Thanks!