ekanson

Hi everyone. I'm new to Lexus. Picked up a 2010 450h recently. After a few weeks of enjoying the car, I'm hearing this noise usually when the car sits for some time before moving. It increases with speed. Usually when it happens, I slow down and park for a few seconds... resume driving and noise is gone. It is very obvious which side the noise comes from as there's a shake on the passenger side and loud enough to tell it's from the RR. I've attached a recording I've made to see if anyone can help identify what that is. I've taken it to Lexus and they couldn't replicate the noise. After visual inspection, they suspect it's my tire but I highly doubt that. Took it in to an indie mechanic and went on two test drives with him on separate occasions and noise wouldn't come on. Put on a hoist, got someone to start the car and accelerate while a whole team went under the car with stethoscope and all and couldn't find anything wrong. Bearings are fine both Lexus and indie mech are saying. My gut tells me it's the bearing but I'm no professional. Thoughts?

salimshah

Diagnosing over the net is always hit or miss.

Based on frequently reported problem it might be the shock absorber.

For remote diagnosis try to isolate the issue

Noise coupled to up/down movement of the side [RR] --- test on a pot hole or a road hump and smooth surface on left side.
Noise coupled to rotational speed of the wheel .. test on a very smooth road
Noise coupled to braking system
Does the auxiliary brake system work as intended
Noise based on torquing .. Standing still to rapid acceleration, right/left turn, stopping, driving in snake like motion with rapid change of direction (stay safe).

On the vehicle ,,, Jack the end up and look for loose items,
Use a light and see if you can spot scrub wear marks.

Also make sure nothing is loose in the back. Take off all carpet/panels and see if the battery [RX450] is secure.

Salim

PS: Try driving near dealership or the mechanics shop and see if you can locate a spot where the issue manifests and tell the shop that spot or ask if a rep can ride with you.

ekanson

Thanks for the reply and suggestions for diagnosing.
Noise is definitely coupled to rotational speed of the wheel. If it happens, it starts after a few feet of moving regardless of road surface condition. I once noticed a clunk when the noise was happening and I happen to go over a bump on the road. But after I park for a few seconds, noise disappears until the next time car has sat for a while.

The indie mech did the snake driving when we did the test drive and car was quiet.

With regard to bad shocks, do they make noise that are coupled to rotational speed? Shocks are on my to do list anyway. I saw Toyota shocks on the rear when I removed the wheel to check for looseness. I don't see shock replacement in the service history Lexus provided me so I'm thinking they've not been replaced.

salimshah

Shock absorber problem is due to leak. One can observe trace/path of oil like substance [usually dried, but with dust/dirt sticking to it].

Since 2 mechanics have already taken a look, I would suggest raise the wheel and remove the disc-drum to see if there is an issue with the parking brake mechanism.

For this you need to be slightly advanced DIYer. Typically mechanics may shy away if they are not assured 1/2-1 hr of labor time.

Salim