Screeching Noise When Engine Cold

[ROGHAY98]

My E320 CDI (year 2000 on the W plate automatic:confused) makes a nasty screeching noise when i first start her up in the morning, i took to the garage as i thought it was the fan belt slipping. It has had a new tensioner and fan belt on it.

The mechanic thinks it is something to do with the climate control/air con unit as this is where he thinks the noise is coming from. If you take your foot off the accelerator it stops but when you put it back on there sounds like a grinding then screeching noise.

It only happens for the first 10 minutes or so then not a thing.

Does anyone have any ideas please. Many thanks
Roger

 

[television]

This still sounds consistant with a belt problem, and nothing to do with air con.

Sounds more in line with the alternator loading from a cold start, is the battery the original

 

[ROGHAY98]

I don't know only had the car a couple of months, i have had a look at the battery and there is not a mark on it. It looks brand new.
Regards

 

[television]

I don't know only had the car a couple of months, i have had a look at the battery and there is not a mark on it. It looks brand new.
Regards

They do look new these days after many years, you really meed to know the voltage across it before you start the car in the morning

 

[carabind]

try some belt dressing first (not WD40) on the belt. They can slip when worn. If that works, you've eliminated the aircon compressor which isn't cheap!

 

[malcolm E53 AMG]

Sounds very much like a belt problem. I would change the belt for a genuine part. I have heard of new belts giving problems even OE supply. As TV says the alternator is loading the belt after initial startup for 10mins or so, this might be enough to cause the belt to slip slightly.