Bonobo

Hi folks,

Any ideas about this ? It's emanating from my 93 standard cx hatchback - somewhere around what I think is the crankshaft pulley. It might also be coming from the alternator but the timing of it (about 3 or 4 beats per second) seems to match the crankshaft speed. I'd have assumed that all belt noises would be squeals, so I'm wondering if it's possibly a bearing about to fail?

I only notice it when idling. It had the timing belt replaced a year ago and a new distributor a couple months ago.

ezone

General ideas, assuming the noise comes from the end of the engine where the belts are:



Use a stethoscope (long screwdriver or wooden dowel held to your ear) to locate the loudest area

Remove first accessory belt, run the engine, see if noise changed (it's only got an alternator?)
If the noise quits after removing the belt, stop and spin that pulley by hand and listen for the roughness,,,,and check mounting hardware for that accessory

After belt is removed, grab the crank pulley by hand and wiggle/push/pull to see if the outer ring has come loose, unbonded from the rubber ring


If noise is still present after all accessory belts are removed, see if the timing belt is so loose it's slapping the plastic cover


HTH

Bonobo

Thanks for the detailed answer. The "stethoscope" is telling me it's either the alternator or the bottom half of the plastic housing around the timing belt. I'll try removing the accessory belt tomorrow.

...and yes, it's just an alternator. This was my first car, 22 years ago and I couldn't afford air conditioning or power anything. The only option I got was a right hand rear view mirror. Even floor mats cost extra back then.

Bonobo

I took it to the shop and it turned out to be a dying water pump. When I had the timing belt replaced last year, the mechanic said that a new pump wouldn't be absolutely necessary (I'd only put about 15k on it in the last 5 years, so that sounded reasonable).

Thanks again for the help, ezone.