tmryan

My wife's 2010 e350 w212 cooling fan seems to make a lot of noise --when running it sounds like a jet engine. Inside the car she can't hear it but once you exit the car you can hear the fan running on high.

The car runs fine with no overheating issues at about 87 degrees. I have an older 1997 e320 w210 that is much quieter.

Are the w212's just noisy or do I have a sensor issue?

pb39374

interesting b/c mine is the same way (2010 E350). I thought it was just normal for these cars. Let’s see what others say.

tmryan

Does yours seem to run on high?

pb39374

I’ve only used the AC twice as the weather just started to get warm. But I thought it was weird once that even when the car was turned off, the fan still ran (very loud) for a few minutes.

tmryan

same with my wife's car. lets hope some other members can confirm that all e350's of that time period have the same problem.

KEY08

My 550 also sounds like a 747, but only when the system is taxed and needs the extra cooling. It doesn’t last very long before it slows down.

kajtek1

1997 E320 has 2 fans, where mechanical fan turns with the engine, meaning not much noise at idle.
Single electric fan will run at full speed with AC on and it will sound like jet engine. No way around other than keep AC to minimum.

xMaximus

From my experience with a 2010 E350, there is also the possibility of the secondary air pump making the noise. Mine had dust build up over the years and it gradually made a loud supercharge-like whine. The unit commonly turns on at start-up and intermittently when the car is idling. If I recall correctly, it works hand in hand with O2 sensor. What I noticed is the unit does considerably turn on more frequently in warmer weather. After I changed it, the whine-like noise went away. Hope this help.

Sunnyslope48

When both of the fans run full blast on my 2016 E350 engine off, they're LOUD when you're outside, not so much inside the car. I suspect what you're hearing is normal.

DFWdude

The fan on my C320 (W203) is loud and always has been. Same with the W212. Unless you are getting alarms, I would suggest this is normal.