my 01 LS430 Ultra has a harmonic vibration problem that won't go away.

At highway speeds, it occurs with a frequency of about 1 second, just a slight pulsing drone throughout the cabin, sounds like its coming from the front right wheel. I can slightly feel a pulsation through the steering wheel also that coincides with the audible drone. The car does not pull to one side, tracks straight. (If anyone has had nitrous at the dentist, it sounds like the wowwowwowwowwowwow in your ears when your on the happy gas.)

I initially thought the old tires were worn unevenly from the previous owner not having the car aligned, because when I bought the car in '04, it needed an alignment. I've recently had new tires installed (Kumho Solus KH16) which reduced the vibration but didn't eliminate it. (Previously had Continental TouringContact tires.) The car has been aligned numerous times at the Lexus dealer, tires balanced at Discount Tire with the Hunter machine.

I mentioned it to the dealer when they did the last alignment, they couldn't find any evidence of damage to the front suspension - said it was the "fancy tires" (my Kumhos are "fancy"???).

HERE'S THE KICKER - when driving down the highway, if the road curves to the left, the drone becomes more apparent as I turn the wheel to the left slightly. If it curves to the right, the drone disappears completely. So if weight comes OFF the front right, it goes away. Put more weight or strain on the front right, and it gets worse.

Could this be a wheel bearing issue? Doesn't really seem like a balance or alignment issue.

Any thoughts?

 

Did you check the engine mounts and the transmission mount, loose swaybar mounts, A-arm bushings, or just as simple as your front under engine pan is loose somewhere? Just some thoughts, good luck...

 

How about wheel bearings? I had a Honda that did that. Freeway speed droning, and then on wide sweeping turns, the sound goes away. It turned out that my right front bearing was bad, after the fix, all is good.

 

I'm hoping its a wheel bearing, it sounds like you had the exact same issue.

Its not anything loose, I had the engine and tranny mounts done 5k miles ago at the 90K service. I noticed it when I bought the car with 30K miles, but I had 20's on it for quite some time. Didnt notice it when I had the 20's cuz of the tire noise, etc, but as soon as I put the stockers back on a few months ago and got new stock tires, it is still there.

 

Problem solved!

Turns out it was an alignment issue. Apparently at one point some idiot aligned the car and did so in such a manner that one tie rod end barely had any threads to connect and the other one was almost bottomed out. While technically the car was always "in alignment" and tracked straight, it wasn't correct. There was far too much adjustment room on one side, and not enough on the other side. The wheel bearings are fine.

The shop who noticed it did so after I had them replace both front air struts and control arms, ball joints, etc. They had to remove the steering wheel, adjust the tie rods so they were even, align the wheels, then reset the steering wheel cuz it was so out of whack. They said that it was in alignment but that if I put the air suspension on HIGH that it would be out of alignment.

So that makes sense, every time I would turn to one side at highway speed the inner side would lift, causing a change in the noise. 100,000 miles later, problem is fixed. The shop that fixed it was Toyomotors in Phoenix, very professional. Looks like Bell Lexus dropped the ball, as they performed the "alignment" several times and kept it incorrect.