Ok.....about a month or two ago I started getting this strange noise at moderate speeds, usually above 30 or 40 mph. I can only describe the noise as the sound of an airplane propeller (I had someone in the car the other day who joked "it sounds like we are going to take off!"), or maybe the sound when you drive over the rumble strip on the side of the highway....but not as loud and there is no vibrations whatsoever. Here comes the strange part.....when I let my foot off the gas at high speeds I swear the noise gets louder. Also when I take a right hand turn with some decent G-force the noise stops then quickly returns when the vehicle gets straight again out of the turn. It has to be a right hand turn only.....nothing changes with a left hand turn. It also has to be a decent turn, a gentle corner won't make the noise go away.

I thought it could be two things:

- Tires. When this noise started my tires were getting pretty bad (bald). So I replaced the tires yesterday with 4 brand new Michellin Lattitude HP tours. Second I get moving up to speed the noise is right there again. So I guess it wasn't the tires. I can't imagine these new tires make that much road noise

- After market muffler. About three or four months ago I put a Flowmaster muffler on my ML430. Sure there was a decent amount of highway droning when I put it on but I never remember it sounding like this. Never like I had an airplane propeller attached to my rear. And why would the noise go away under a hard right turn if it was the muffler? Could it be an air leak somewhere?



So now I'm stumped. I don't know what to say to my dealership if I bring it in. Maybe they will think I'm crazy. Maybe they will blame the muffler since it is not OEM? This noise is driving me nuts. Its loud and annoying. I'm starting to dread everytime I take my beast out for a drive.

Help!

 

does the noise appear between 2500-3000 RPM? what if you are at a much higher RPM?

 

Not sure Pete. If I"m at a stop the noise isn't noticable until around 30-40 mph but last until 5-10 mph.
I'll check the RPM's.

 

I'm leaning more towards a wheel bearing. Maybe I should do a search.

 

and some of these cars have the unlimited mile warranty on them "hairline" crack...and it's kinda loud, but not really a propeller sound, more or a clunking, but along the same line... i dunno.

 

The fact that it goes away during a hard right turn and then comes right back when I straighten out has to be the key. Must be some sort of suspension/wheel component. I think I'll get it checked out soon. LOL

 

Finally getting it fixed. Its a bad rear wheel bearing.