Noise diagnosis anyone??

[BIIOAB]

My Chim 500 has started making a noise which I cant seem to pinpoint obviously.
When the engine is running there is constant noise like a dry ball-race? in the sort of upper pulleys/distributor area.
I was thinking maybe take the serp belt off and turn the pulleys to see if anything was obvious.
Anyone recognise this or have any other suggestions?

[Ballistic Banana]

Could be the Alternator, they can make a dry swishing type noise. not sure what teh answer is to cure that appart from replacing?

BB

[Cider Andy]

Yeah, it sounds like the sort of noise the alternator would make when the bearings are on their way out. Is thre anything a DIYer can do to one, if that's what's wrong (I've never had one apart)?

Could it be the idler pulley on the belt tensioner?

Does it have power steering? Mine makes that sound, although only under load.

[GreenV8S]

Borrow/buy a mechanic's stethoscope, or use a long handled screwdriver as a crude alternative. Noisy bearings are very very obvious through a stethoscope by the time they are loud enough to be heard by the naked ear.

[Mad Mitch]

Try spraying the serp belt with some rubber treatment spray or a silicon spray. These belts when dry can make the sound you are describing. Not too much spray or you"ll make it slip. Not a permanent fix though, if it stops it, fit a new belt.

[BIIOAB]

Thanks for the quick replies, guys - I tried a crude version of the stethescope (a bit of wood!} and it wasnt very conclusive.
Thought about the spray also before I start to take things apart - exactly what kind do you recommend?

[Cider Andy]

Fourth one along is good stuff:



(as are some of the others).

[GreenV8S]

If it's belt noise, you want top make sure the belt is clean (no debris pushed into the surface) and then use belt dressing spray. I would advise against using any lubricant / grease sprays as hese make the belt more vulnerable to slipping rather than less. It might make it quiet, but a slipping belt isn't going to last very long.

[parrot of doom]

Does the frequency of the noise change with revs (ie more revs = higher frequency)?

[Flintstone]

Take the belt off and spin the pullies and alternator one by one.

If it's the same problem you'll identify the bearing that's on its way out quite easily. A doddle to replace but make sure you put the new pulley on the right waay round. Easy to tell as one side is marked 'front'.


(Don't ask me how I know this )

>> Edited by Flintstone on Monday 19th September 20:49

[BIIOAB]

parrot of doom said:

Does the frequency of the noise change with revs (ie more revs = higher frequency)?

Yes it rises and falls with revs - no louder though....

[BIIOAB]

[quote=Flintstone]Take the belt off and spin the pullies and alternator one by one.

If it's the same problem you'll identify the bearing that's on its way out quite easily. A doddle to replace but make sure you put the new pulley on the right waay round. Easy to tell as one side is marked 'front'.


(Don't ask me how I know this )

What pulley did you replace then?

[parrot of doom]

When my alternator went a few months ago it made exactly the sound you describe - a distant whining rising and falling with revs.

[Flintstone]

BIIOAB said:

What pulley did you replace then?

Actually I had to replace the alternator and the idle pulley (PAS on later models) as both were noisy. Pretty straightforward though.