'Chirp'/squeak noise on engine start/stop

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sgregory124

MB Enthusiast
Joined
Sep 11, 2004
Messages
1,167
Location
Derbyshire
Car
E63S
Afternoon all,

Just been on a 45 mile round trip for petrol (why not - nice day for it right?!), whilst sitting in traffic, eco/comfort mode does its thing as usual and kills the engine. Since I had the windows down I just noticed a relatively loud 'chirp' or squeak noise coming from the engine on both start and stop. It sounds like a tropical bird under the bonnet, for about 1.5 seconds until the engine is running.

When I stopped at the filling station I tested to see if the sound would happen when shutting the car down with the button, which it didn't. On startup after feeling the noise didn't occur then either. So it appears it only happens when the car stops or starts in eco/comfort mode.

My initial thought here is a dodgy belt somewhere, but if that's the case why doesn't the car do it when using the button to start or stop? Also, surely the car is using the same mechanism to start and stop as it does when you do it manually??

Hoping this isn't a garage visit given it was only serviced 5 weeks ago and i've only done 400 odd miles since!

Car is a W205 C63S, any suggestions considered, thanks in advance :)

Simon
 
Any ideas anyone? Tested the car again today and the noise is still there so it looks like its off to the garage I go....:\
 
Whilst not generally in the habit of replying to myself, I thought i'd update this thread in case anyone else is having a similar issue. Whilst I don't have a conclusive answer (as the car is still being diagnosed and staying at the garage over night), it is looking very much like a starter motor problem.

Might have a stiff drink later and prepare myself for the inevitable wallet destruction!
 
Hi, i have the exact same problem... i just noticed it today with windows open in traffic... was it the starter motor in the end? thanks Lee (2018 C63S)
 
Could it be a belt slipping?
 
If it was a starter problem wouldn't that be as the belt, not on manual start only on eco, 🙄
 
Thanks for feedback guys. Yes I get what your saying. I be interested to hear how Simon got on
 
Thanks for feedback guys. Yes I get what your saying. I be interested to hear how Simon got on
Ok so mine was the starter motor ‘bendix’ drive, all the lubrication had dried out, luckily didn’t need a replacement though.

The garage removed it from the car, re-greased it and refitted. I paid £220 for the labour, but that was with additional diagnosis when we thought it was a worn belt or pulley. So you will probably pay less if that’s your issue.

That price was from my local independent. Hope that helps!
 
Ok so mine was the starter motor ‘bendix’ drive, all the lubrication had dried out, luckily didn’t need a replacement though.

The garage removed it from the car, re-greased it and refitted. I paid £220 for the labour, but that was with additional diagnosis when we thought it was a worn belt or pulley. So you will probably pay less if that’s your issue.

That price was from my local independent. Hope that helps!
Thanks Simon. Appreciate the feedback and glad you got it sorted.
 
Ok so mine was the starter motor ‘bendix’ drive, all the lubrication had dried out, luckily didn’t need a replacement though.

The garage removed it from the car, re-greased it and refitted. I paid £220 for the labour, but that was with additional diagnosis when we thought it was a worn belt or pulley. So you will probably pay less if that’s your issue.

That price was from my local independent. Hope that helps!
This kind of thing is what makes the forum so great. If only everybody who finds a solution to odd issues posted back with the resolution!
 

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