Alba108

Hi all,
Got a 2011 E350 that has developed a whining sound in the front end. Its not audible unless the car is moving. Does not appear to vary with RPM. It does increase in pitch as the car gets faster and reduce as the car slows.

Originally I thought it was a cabin fan or sound via speakers (like grounding issue) - does not appear to be either.

Any suggestions on things to check as route of investigation or ideas on what it might be?

Thank you in advance for your input.

Senecat

Wheel bearing.

Fliplegend

If not wheel bearing, possibly unbalanced wheels/tires.

atraudes

I'm also guessing wheel bearing, but there is a bearing on the drive shaft that goes through the oil pan that could be bad too. Once you get the CV axle off it's pretty simple to get the shaft out to look at the bearing.


I wish it was easier to check the level on the front differential, otherwise I'd say check that and make sure it's not dry. If you don't know how long it's gone since the last change, it's worth doing anyway.

If it is a wheel bearing, the sound will change when you turn. Maybe find an empty parking lot and do some experimenting.