2015C3004Matic

I have a 2015 c300 and it’s making a annoying whining noise under acceleration sounds like it’s coming from the turbo, I took off the intake and didn’t see any problems. What could it be?

James_H

I had a whining sound on my previous car, the alternator died shortly after which totally shut the car’s electrical system off except the engine. That should be easy to get tested at Autozone or a mechanic.

matt.jessop

I had a whining noise in mine too - divorced her and it went away

#OldJokesAreTheBest

2015C3004Matic

I will get that checked I think the car has a built in voltage reader too I have a video of the sound too it changes as you shift gears

Keith66

Agreed, good first guess and what I would assume also. If the whining sound aligns with RPM, I say alternator first, accessory drive belt(s) and/or belt tensioner(s) second.

2015C3004Matic

alternator is fine I am wondering if it could be a small boost leak because there is no noise when you rev it in park but only when the turbo is spooling, I changed the air filter and messed with bunch of hoses and stuff and I think the sound is a little less today.

Keith66

That's good news! I can't really hear it well in your video. Do you have an OBD scanner to check what the ECM is seeing?

2015C3004Matic

I checked the codes but nothing, I am gonna do a boost test this weekend and see if anything changes.

sixmarch

Did you ever find out what the issue was with the whining? Having a similar issue on my vehicle.