tbone

Hard to describe the sound. Not a grinding sound. More of a "whir". It happens only when the car is cold AND I make a 3/4-to-full lock turn (e.g. I'm backing out of the driveway, turning onto the street.

Once the car's warmed up, and I make those turns, there's no sound.

Any thoughts?

Devilsfan72

Your power steering fluid sounds low.

tbone

Should I be worried (leak, other issue) that the level is low? Or does this happen? Car's over 4 years old (72K miles). Should I bring into the dealer?

Is topping it off a DIY job?

211E350Black

you should top it off with the mercedes benz power steering fuild and the cap has markers where the fuild should be

EmergencyDpt

I agree, powersteering fluid.
Might also be the belt.
Keep us posted.

vettdvr

It could be normal if your system is not low on fluid. Ours has been making a "simular" sound since new but only cold. I think it is the clearance on rotary vanes in the power steering pump. Ours is not an abnormal sound, after start up/warmup it goes away. Jim

tbone

Yes, it's weird in that the sound goes away after the car warms up. Did you ever take your car in to check out? I've noticed the sound for months now, and have just been lazy to bring the car in. But I've noticed the sound starting to get louder, so I'm starting to wonder what the cause is.

vettdvr

If the sound is getting louder, the pump could be in a failure mode. There are vanes in this pump that have very close tolerance to maintain the pressure and angles needed for operation. If the slots for the vanes are wearing open the noise will begin to change. Doesn't mean instantenous failure but failure in the near future. I would recommend having it checked if the sound is changing. Expect to pay big $$ for the power steering pump. Jim

tbone

Well, I certainly hope that's not the case. Would the pump be covered under the extended warranty?

vettdvr

I would expect a powersteering pump to be covered under the warranty. This is why you should have it looked at. Since the noise is getting worse it might be worth the effort. Jim

tbone

I finally got around to visiting my dealer. They topped off the power-steering fluid. The sound is gone...it's been a week so far. Thanks for your help guys

Musikmann

Glad to hear that's all it was. We have different cars, but when I had a pre-winter check-up last fall, the tech had to add some power steering fluid to mine. I was charged for 1 bottle, but I don't know how much he actually added. I don't remember ever hearing a noise like you described, so maybe it was not low enough for that to happen.

vettdvr

Where did the fluid go that made it low? Leak,, if so where.? Jim

Musikmann

I don't know, but they never told me I had a leak. I might not have even noticed that they added PS fluid except for the service writer pointing it out. He didn't say this, but made a sound and gave me a look like that was indicative of a problem. If the level is low, it has to be going somewhere doesn't it? If it's a completely sealed system, which I believe it is, I don't think it can evaporate or dissipate into thin air!