Mystery Noise

[anonymous-user]

When I rev my car as the revs fall there is a rattily chain/harmonic type noise from the engine on the inlet side.
Tonight whilst looking I put the air con on and when engaged the noise does not occur!
eureka!! . I then remove the belt from the air con pump. Start-up expecting success and the noise is still there!!

So bit of a mystery, it definitely went with air con pump engaged.
Is it possible that under load the lower chain is less noisy, but with no load, air con off or belt off the noise returns.

What are the thoughts please?

[330p4]

Electromagnetic clutch on aircon compressor ?
Ian

[anonymous-user]

You are absolutely correct, removed compressor and noise has gone.

Thanks for the response

[VARLEYHYD]

Trinary switch fault causes the compressor rattle

G

[M50GRF]

I have possibly the same noise/problem which starts at 3k rpm, when I took off the aircon belt the noise went, I have now replaced the aircon compressor and the noise is back, also when the engine is hot (oil above 75c) the noise goes.
Could it be the bearing on the aux shaft now its under load again?

[anonymous-user]

What about the chain that runs the take off. It does have a lower chain adjuster, a bit more complex to adjust than the top one,but adjusting this has taken my engine back to almost 'ordinary' engine noise levels.

[M50GRF]

I Didnt know you could adjust the lower chain can this be done with engine in and cover on?

[anonymous-user]

Yes there is an adjuster at the bottom, you may need to take the power steering pulley off to see easily. It is a different type of adjuster to the top but not a big job.
Have a look at the post about 10 down from here, 'lower or primary chain adjuster'