khelms98

This is one of those noises that could have been occurring since new, but I've just never really noticed, or it could be new, I'm not sure. Anyway, on my 2010 E350 with 55k miles, I have a very slight whine from the engine at lower rpms when driving after being parked for a while, ie. overnight or at work all day. It is definitely rpm-related as I hear it as the car is revving and picking up speed, but I also hear it if I rev the engine in park. I did quite a bit of driving today and I noticed that the whine wasn't present after the engine and drivetrain components were fully warmed. Any ideas, or am I being too finicky? It's not a painful dang-what's-that-noise kind of sound, but once you've heard it, it's hard not to hear.

On a possibly related note, on the first crank after being parked for a while (overnight, work...), I get a rhythmic chirp that is most certainly belt related until the engine is warm. My commute is about 5 miles or so and, depending on the ambient temp, the chirping could still be present when I get to work. Could this all be related to some type of pulley, tensioner (dealer mentioned that), or simply the V-belt that needs replacing???

Please give me your thoughts. What should I check first? At 55k, I'm out of warranty.

ttoE550

Had the same thing in a different car. The belts needed to be replaced. Good luck.

khelms98

Thanks so much! I was hoping it was something as simple. I was told the chirping could also be a belt tensioner, but perhaps just the belt replacement will do the trick and correct it all! Thanks again!

mnje350

Noticed a whine on the wife's CLK350 then realized my '10 E350 has the same whine. Sorta like a power steering pump that is going. I have now heared it on several MBs. I think it's the nature of the car. Sound goes away or is not noticeable above 35-40 mph.

khelms98

Does the whine on either vehicle go away, or at least seem less obvious, after the engine and drivetrain has warmed fully? Mine seems to have this characteristic. Like I said, it could have been there all along because it doesn't sound bad or even faulty, but once I noticed it, it became hard to un-hear.

mnje350

I have not noticed if it goes away when warm. I mostly notice it at very slow speeds when in the driveway or when the top is down on the wife's car at very slow speeds. I will listen to see if it is less noticeable when the engine is hot. I recently had a loner GLK350 and heard the same whine on it so I am thinking it is typical. I agree it is hard to unhear this sound. But I am growing less and less concerned the more I hear it on other Benzes.

khelms98

I agree! It certainly eases my mind knowing that others do it as well. I drive a lot (55k miles on a 2010) and I'm very particular about maintenance so when I first noticed it, I wasn't sure if it was a normal noise that I simply hadn't noticed or a latent problem waiting until after my warranty runs out. I just hope we're referring to that same whine...mine starts at a good rolling speed and ceases (or is less easily heard) above 30 or 40mph.

Thanks for the input! I expected nothing less from this forum!

khelms98

I've been reading some other threads in different forums and I've heard people mention idler pulleys going bad and causing a whine...but would a whining noise go away when the engine is warm if this was the case? Just wondering....thanks!

If I decide to take it to the dealer, I'd like to have something to tell them since I'm all out of warranty.

mnje350

Mine has been doing this since new so I don't think the idle pulleys are guilty in my case. You mentioned a chirping earlier in this thread. That is not something I have heard.

khelms98

Yes, the chirping is only after starting the car after it has sat overnight or all day at work. It chirps until the engine is fully warmed and has been driven a few miles. My dealer told me to take a spray bottle of water and spray the belt as it's chirping to see if the noise ceases for a moment to determine if it is indeed belt related. I did this and the chirping stopped for a second or two so I'm guessing the belt could use replacing regardless, either that or a tensioner (per dealer).

dvpriem

I have a different type of noise. While gently accelerating or decelerating between 70 and 75 MPH I get a fairly loud, high-pitched whine. Is it an engine bearing or rear end issue? Car has only 140 miles on it now. The sound is louder than the radio, very pronounced. It is not like a belt slipping sound. Sounds more metallic like bad gears or something. Any ideas on what this might be? My dealer is 120 miles away so I want to educate myself before bringing it in. Anyone else hear something like this? Never had it on my 2010.