Seattle SCone

For about six weeks a soft tinking noise had vexed me every day. It was soft and sounded similar to a hose lightly hitting metal. Location seemed to be from the right rear of the car. It only would occur at very low speed and unreliably happened with road unevenness smaller than a man hole cover in depth. Large ruts, curbs, and speed bumps would not trigger the sound. It wasn't associate with using the brakes. Lowering my windows didn't allow me to hear it any more loudly. In fact, lowering the windows made the sound inaudible. The only reliable noise, I could elicit with large bumps was a soft bushing squeak from the rear sway bar.

Worst of all, the tink didn't reliably occur going over the same stretch of road. It would inevitably happen when I dropped to < 15 mph. Gear didn't matter. Accelerating, decelerating, revving engine all without triggering the noise.

I looked for multiple possible sources like loose bolts, heat shields, braces, hoses, brake clearance, dust shield, suspension bushings. Lifted the car multiple occasions to check things. Found and corrected a loose bumper clip, a loose exhaust tip, and one trunk cushion. Nothing made the inevitable, but unpredictable noise. Just infuriating to hear that tink, tink at low speeds. Tried listening with windows down next to a wall. Nope. Heard nothing.

Annoyed doesn't begin to describe how I felt any time that noise appeared. Utterly defeated my best efforts.

Finally, decided to locate the "tink" noise source with more than my ears and inspecting things that might be making that type of sound.
It wasn't cheap, but OMG it was worth it to get rid of the damned noise.

Enter the Steelman Chassis Ear - a wireless, multichannel, clamp-on microphone system.



You attach a microphone clamp at each candidate location. Then secure the transmitter for that microphone in a safe location.
Here is a microphone attached to a sheet metal shield that I suspected might be hitting the muffler. Its transmitter secured with velcro straps.




I planned on multiple attempts to narrow down the noise location. My first run instrumented lower control arm (in case of one of its bushings), fuel tank strap, sway bar, and metal shield.
If lucky, I could get the sound to happen often enough to see if one of the microphones picked up the same sound and was louder than the others.



I was not looking forward to multiple lifts, relocation of microphones and test drives, but I was determined to narrow down the damnable noise.



So I drove about slowly and switched amongst the channels in hopes of getting the noise to occur and show up on a mic. Then, I would narrow down the location by moving the microphones until I got a channel to get the noise most intensely.

Totally, lucked out!!!!! The sway bar microphone immediately was noisier than all the other locations despite my not actually hearing the noise with my ears.

It was the sway bar, but not its bushings nor the bushing mounts. The connection between sway bar and its link stud was the source. It wasn't until I detached the bushing mount that I could make a click manually pushing on the sway bar. That was enough to create the soft tink noise I was hearing. Solved the issue by peening my sway bar's aluminum diameter reduction bushing I had previously made to fit the ISF sway to my SC430's links. Basically tapped the bushing's ends to mushroom it slight to get a tight press fit. Then, I torqued up the link stud to press the aluminum reduction bushing into the sway bar. New grease for the bushing and repeated for right side.

No more tink noise!!!!!

Most interesting is that the sway bar would not make such a noise on larger bumps or uneven ruts. Only with very small tilts would it make the noise. Because of that behavior and the fact that manually shaking the link (with bushings mounted) didn't do anything, I had practically ruled out the sway bar.

The Steelman cost $200, but was worth getting the noise problem solved. I'm sure there could be cheaper means, but after weeks of dead ends, it was fantastic to locate the culprit in a single test drive.
There is a lower cost, wired version with six microphones, but I really didn't want to mess with routing a bunch of wires. The wireless transmitters are super quick to mount. Their on/off slide switches suck, but that I can forgive after solving so vexing a noise issue.

Effective and definitive. I'm glad I got the Chassis Ear.

Harold57

Very cool Seattle SCone. That is a pretty cool tool too. I didn't even know those existed. Great detective work! Congratulations on your discovery and solution.

Seattle SCone

To help newer readers who started reading at this thread....

Creation of the aluminum reduction fittings was detailed near the end of my thread on sway bar installation. Initially that thread was about the front sway bar, but also ended up including rear sway bar replacement with the ISF rear sway. Also, we learned about the paint mark on the Lexus sway bars helping to indicate left/right end. I originally had my rear sway bar backwards. Removing and reinstalling it was probably when my tie stud ended up too loosely torqued.
https://www.clublexus.com/forums/sc4...-sway-bar.html

Associated suspension refresh to completely transform the suspension system behavior was discussed in https://www.clublexus.com/forums/sc4...project-4.html