a moaning sound; what's that?
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Joined: Sep 2011
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2009 E350 4Matic Sport sedan
a moaning sound; what's that?
('09 E350 4Matic w/44K miles)
For the first few blocks (until warm-up), my car emits a low but discernible moaning sound. It follows engine speed until reaching about 35 mph, at which point normal road noise, etc., covers it up or the engine temperature reaches normal operating levels.
The only variable is...if I turn on the A/C, the sound stops! In other words, the sound only occurs when the A/C is turned off; and again, the moan only continues until the engine is warmed up.
Have others noted the same thing?
Comments, please.
For the first few blocks (until warm-up), my car emits a low but discernible moaning sound. It follows engine speed until reaching about 35 mph, at which point normal road noise, etc., covers it up or the engine temperature reaches normal operating levels.
The only variable is...if I turn on the A/C, the sound stops! In other words, the sound only occurs when the A/C is turned off; and again, the moan only continues until the engine is warmed up.
Have others noted the same thing?
Comments, please.
MBWorld Fanatic!
Joined: Mar 2004
Posts: 5,017
Likes: 16
From: Ft. Lauderdale Area, USA
2015 ML 350
I've got it too, but mine does not change pitch with engine/vehicle speed. It just fades in and fades out a lower & higher parking lot speeds untill the car warms up.
I've been told its a pump for/in the transmission.
I've been told its a pump for/in the transmission.
Last edited by Barry45RPM; Jul 27, 2013 at 10:48 AM.
