Yes, yet another question on suspension. Apologies for those who have seen this before... I searched archives but didn't see anything specific to this. Okay, here's the story: I've been to three different indys. A Benz specialist, a foreign auto generalist, and a tire/suspension shop (only one to hear problem). The first two were not able to replicate, the third heard it, but wasn't sure what it is.

Problem one: Accelerating while turning right, especially on a freeway on-ramp circles going up. Rapid clunk-clunk-clunk from the right front (side being turned into). Stops when easing off the gas.
Problem two (related?): A clunk-clunk when I take foot off gas to coast or decelerate. Lighter and less noticeable. Goes away if steering turned off center to either side.
Problem three: Swirling/swooshing sound sound that is intermittent. More of a light swooosh or thub-thub.

All three are from right front side. All three are intermittent. The tire shop that heard it said maybe strut going out for the clunking, maybe a differential bearing for the swooshing. Both sound like possibilities. They couldn't fully diagnose and basically said just start replacing stuff and see.

I was going to start with the strut as it looks pretty straightforward for me to do. I'd need to take it in for diff bearing, or hub bearing, but don't want to do that if it's a shot in the dark. Suggestions? I'm in Inland SoCal, and don't mind travelling to a (reasonably) close specialist if there are any recommendations.

Also, where is the best place to buy an Arnott strut from? Direct from them, or ???

Thanks, all... hoping to have this fixed so the vehicle can keep chugging along. It's an '07, but with low miles in the 80k range. We want to keep this going for a long time, as we love it (especially now that gas is cheap). So far no bearing wear from the engine that we've been able to diagnose via Blackstone, so just need to keep up on this other stuff.

 

How 'bout something going on with the brake dust shield? Maybe bent slightly were it rubs at certain times? The right side shield on my BMW does this on left hand turns - every so often I have to go in there and bend it back a bit. I know, sounds strange, but there is just enough flex in things that when putting pressure on the right side (turning left) it causes things to get a little closer together. Truth is, I'm only about 90% there to getting this completely figured out - but I know I'm in the right spot. The tipoff for you is if the noises/swooshing, when it does happen, seems to jive to tire speed rotation.

 

Thanks! It almost sounds like that, the way it only comes on during right turns. I've poked around and tried to see if it was wheel rub on one of the fender well panels, but didn't see anything. I'll take another look at the dust shield!!

 

Right turns unload the front right wheel to some degree, is the clunk rhythmic with speed?

 

Yes, correct, it would be the inside of the turn. It only happens under specific circumstances, lets say accelerating from 20-40MPH while turning right. Wheel has to be turned pretty good as in a freeway on ramp cloverleaf. Goes away as soon as gas is lifted off of, as well as when the turn is completed and I've straightened up.

The other noise on deceleration is different. Same rhyhtmic, but less of a thump, and more of a light whump.

I should be talking to Click and Clack with all my noises...

 

There are so many things on these trucks that make all kinds of sounds in the the steering and suspension.

Take a look at bushings on the steering rack as a cause from this other thread: https://mbworld.org/forums/gl-class-...ml#post7981890

or the links: https://mbworld.org/forums/gl-class-...ml#post7980329

 

Rotate the tires and see if the sound follows.

you’d also spot anything rubbing at the brake shield when you rotate tires.

 

This sounds logical - I originally thought the same thing, which is what made finding the noise on my BMW so hard. But in my case, there was zero noise when spinning the tire - it needed weight on it to make the noise.

That said, this may not be the issue, of course - just thinking outloud.

 

by rotating the tires I mean unbolt and move it from one corner to another (front right to rear right in this example) See if the sound follows the wheel and tire combo.

 

Ah, gotcha. That's a good idea - if nothing else, it eliminates a variable and it's easy/free to do!

 

Too hot to do anything these last couple days, so will have to dig into this weekend.

FYI, the loud clunk on turning was there prior to my previous tire rotation less than 5,000 miles ago. It's just gotten worse since then!

 

Another easy thing to do (to at least eliminate a variable) is to disconnect BOTH (just to be sure) sway bar end links and drive around.

 

I raised the suspension so I could crawl under for a quick look, and noticed the compressor is riding on the wheel-well panel. That caused a good chunk of rattling. So I think that is one of the problems, an intermittent clunking noise whenever the compressor fires off. That might coincide with noises happening more often when cold/just starting off. That's when the compressor kicks in to top off the air shocks. I don't think it explains the clunking during hard turning while accelerating, but it's one of the sounds. Now to figure out how to isolate the compressor so it's not touching the trim piece!

 

The clunk, clunk at low speeds while turning sounds like your front CV joints need inspection (inner and outer) or possibly fresh lube. Also, if you jack up one side of the front and grab the wheel to torque back and forth (pushing in/out) that might let you know if there's a worn hub or compromised bearing - although a bad bearing would howl like crazy.

The clunk when you take your foot off the gas is a classic motor mount or trans mount failure. The clunk is usually the engine rocking slightly in place.

On my 2008 GL, I replaced all 4 of my struts in my driveway without air tools. Incredibly easy if you are mechanically inclined. I purchased two struts from Amazon (due to a failure) and then two locally from an independent Import Parts shop. The local price was still about $45/ea higher, but I needed them ASAP.