Noisy A/C
Thread Starter
MBWorld Fanatic!
Joined: Feb 2002
Posts: 6,061
Likes: 326
From: 2000 ft over the FL coast in a B-17
Various
Noisy A/C
I just began hearing a humming/buzzing sound coming from the engine compartment when the A/C is on? Seems to either be there all the time or just when turning a/c off. Sounds like its coming from the A/C compressor. I posted more details in the tech section but please post your responses here.
Thanks all.
Thanks all.
Last edited by RJC; Aug 17, 2003 at 02:19 PM.
Senior Member
Joined: Dec 2002
Posts: 391
Likes: 2
From: Northern Virginia
2010 ML350 GAS 4Matic
It could be the secondary radiator cooling fan coming on when the engine is hot and the AC is on. I used to think my AC compressor was making noise until I figured out it was the cooling fan. This car has the absolute loudest fan I have ever heard on any vehicle. Outside of the car it sounds like a jet landing. Inside, I hear a grumbling sound and the car shakes a little when I'm sitting idle.
I understand there is a tech service bulletin for this where they reduce the speed of the fan. I will have this done at my next visit.
I understand there is a tech service bulletin for this where they reduce the speed of the fan. I will have this done at my next visit.
Thread Starter
MBWorld Fanatic!
Joined: Feb 2002
Posts: 6,061
Likes: 326
From: 2000 ft over the FL coast in a B-17
Various
Thanks Eich. The noise is from the A/C compressor (I put my head as close to the compressor as I could and the sound seems to be there) when I turn the A/C off the noise stops but the cooling fan keeps running at a constant speed. I made a post in the tech section a Patrick an MBTech in Europe said there may be an issue with this new type of compressor (clutch always engaged and an electronic valve controls things). My A/C is nice and cold but the noise is new and dosn't sound right. I get a vibration from the cooling fan too when its running fast, that can be corrected by better securing the fan shroud/housing (my dealer did this on my 03). If you check you'll see the fan assembly is a loose fit not very secure at all and that's a big part of the vibration.
Last edited by RJC; Aug 18, 2003 at 08:26 PM.
