My G37xS coupe has the hotchkis sway bars up front and back. When the font sway bar is set to the stiffest setting, it makes a lot of loud rattling, thumping and clunking sounds after driving on it for about 30-60 minutes. However, on the softest setting, the noise goes a way or becomes barely audible.

Here is how the noise occurs:

1. At first I thought it was the endlinks (Brand New SPL) since re-tightening the endlinks makes the noise go away. However, after driving on it for 30-60 minutes (highway and city streets), the rattling thumping sound comes back. I already tried re-tightening the endlinks (SPL) multiple times and each time the sound comes back after 30-60 minutes of driving. When the rattling, thumping and clunking sounds starts, it occurs most on uneven roads and going over speed bumps.

2. Thinking I had faulty SPL endlinks, I switched back to the Moog endlinks (Brand New). The same thing happens. When the front sway bar is set at the stiffest setting, the loud rattling and thumping sound occurs about 30-60 minutes into driving on it. When I re-tightened the endlinks the sound goes away just to come back after driving on it. As before, when the rattling, thumping and clunking sounds starts, it occurs most on uneven roads and going over speed bumps.

I have already tried greasing the Moog endlinks and the sway bar mounting points and neither of this helped. The thumping and rattling sound only occurs when the sway bar is set at the stiffest setting. When the sway bar is set at the softest setting, no rattling or thumping sound can be heard and if it does occur, it is at a bare minimum. I had two local mechanics take a look at this issue and neither of them can resolve the issue. Both of these mechanics are familiar with G37xS coupe and the hotchkis sway bars. I am honestly at a lost as to why this is occurring, especially only on the stiffest setting.

In the past, I have scrapped the sway bar when going over a dip or uneven road 2 or 3 times, but after having two mechanics who were very familiar with hotchkis sway bars inspect for damages, they both said the damage were cosmetic only.

Anyone have any idea what is causing these thumping and rattling when I set my front sway bar to the stiffest setting? Anyone had this issue before?

 

what kind of grease did you use on the sway bar bushings?

 

Also, don't assume it's the sway bar making the noise. Look at the windshield wiper reservoir and various heat shields around the exhaust. Could also be a loose splash shield or fender liner.

 

I use the one sold by Hotchkis.

I check all that myself and had the two other mechanics (two different locations) checked it too. Nothing was loose. The thing is, the sound will go away if I re-tightened the endlinks when its set to the stiffest setting. However, after driving on it for about an hour, the rattle would come back.

I am so confused as to why this is only occurring when the sway bar is set at the stiffest setting.

 

maybe try reapplying the grease?..the little bit that comes with the sways may not be enough...mine went after a year or so and started squeaking...I think the bushings wear out a bit and need more grease to fill the gaps after a while....I used crappy grease after that but in a larger quantity and it was good for a while it became noisy in less than a year...pushed that out and applied a ton of the hotchkis grease with a grease gun and it has been noise free for a few years now...hopeful its something simple like that...unfortunately diagnosing suspension noises is mostly trial an error...good luck and let us know if/how it gets fixed..

 

Thanks for the suggestion Hashim. I already did that and those grease sold by Hotchkis isn't cheap either. Yeah, I will try to see if I can figure out the issue and if I do, I will update it here.

 

oh ok good, sorry thats alI could think of for now good luck

 

I having a similar issue with my SPL endlinks and Eibach sway bars, mainly in the rear. When you guys say you re-greasing, do you mean the bushings where the brackets go over? I need to tighten my end links down and get the heim joints even/flush as well. It's difficult to tighten them with the wheels on the ground.

 

I greased the contact points between the sway bar and the bushings and the contact points where the brackets meet the bushings. SPL generally makes some clicking sounds over time from my experiences, but it shouldn't rattle, clunk or thump.

For my sound issue, I am changing out the bushings and the brackets in hopes of fixing the problem. My bushings are only 2 years old and I am not sure if that is whats causing the excess sounds.

 

I was able to get rid of the noises for now in the passenger rear. I applied some white lithium grease to the threads/nuts and around the heim joints. The hardest part is making sure you're heim joints are even. I then cranked them down as hard as I could. We will see how long it lasts.

 

Yup, this is what i was talking about.


if/when the grease you applied goes, for a more permanent solution next time try a waterproof (marine Grease) or the specialized grease from Energy Suspension or Hotchkis as regular white lithium grease tends to wash away especially on suspension parts that are exposed to car washes and the elements in general

 

Yeah I was thinking to myself I wonder how long this will last. Appreciate the advice!