My front end is noisy - it rumbles over rough roads and doesn't quite 'clunk' but 'knocks' or 'thuds' over edges of larger road imperfections. It is noisier in general over roads that aren't perfectly smooth.

It didn't use to be this way - cue sob story:
[Once upon a time I had to brake REAL hard in order to avoid plowing some idiot who pulled out for a left turn off a side street. Prior to that, my LS was deathly quiet, especially because I had just put on new Pirellis.

Ever since then, my front end has been noisy. A front shock blew out because of that maneuver, and I replaced the front shocks with KYB Excel-Gs, and also replaced the larger LCA bushings with the IS versions (as seen on ClubLexus). Also recently had to replace the steering rack (used OEM) due a collision with some road debris but that has not changed the problem.]



My front wheels spin freely without noise. There is no play with 12-6/3-9 maneuver.

So now the Q is, in what order to replace parts?

1. strut mounts (not replaced when I replaced the front shocks... wondering if this is the source of all my noise? Is there some way to tell beond replacing them? And should these be OEM with KYB Excel-Gs? Or use KYB mounts?)
   
2. LCA (in order to get new LCA bushings)
   
3. LBJ (again, no play that I can detect in the wheels)
   
4. UCA (because I've heard some people have this as the source of road noise, would include the two new bushings and the upper ball joint)
   

Whichever thing I try, I'm going to do the front sway bar bushings and end links, because they're easy to do and cheap, but I don't think they're a problem. It's all going to be OEM, ordered from Impex Japan as they are way cheaper than any US or UAE vendor.



Other diagnostic maneuvers to try? WWYD?

 

Wheel bearings? But clunks sounds suspension related

 

And wouldn't I have some play when manhandling the wheel?

Also, noise is absent when the road is smooth..

 

1. You need new struts
2. Most likely you will need to replace the lower control bushings
3. Use OEM mounts - use this site to order them https://www.nengun.com - OEM parts from Japan at a great price like $50 each plus shipping. US Dealers want over $200 each.
4. Jack up the car and see if you have any movement when moving the tire. Put one hand on top the other on bottom and shake real hard. If the tire moves it’s other parts that need to be replaced. Upper control arm maybe - etc…
5. Spin each wheel while jacked up if you hear a rough sound then that wheel barring needs replacing - does not sound like your problem since the car rides silent on good pavement.

 

New struts as in.. the shocks? I just replaced those maybe 2-3 thousand miles ago. Not with OEM but the next closest thing.

I also already checked tire movement. There is none.

 

Some new parts are defective and need to be replaced. Just because you put in a new part does not mean it is not defective. It might just be 1 strut that is defective. You should be under a warrantee at 2-3k. If it’s just one side ask for a replacement… When doing new struts always replace with OEM mounts. Without driving the car and looking under your car please take this as only best educated suggestions.

 

Yeah sure, the struts could be the issue still. It's both sides that are noisy. Even going over road markers makes a LOT of kathunking noise.

 

You can buy OEM replacement struts without going to the dealer. You can go on the cheep however they may not perform up to OEM standards as you have now observed and experienced..

 

Maybe you are over thinking this thing.
I had rumble in the fromt end that was noticeable at speeds below 40 mph but went away after that. Really noticeable on rough roads, partly because I was driving slower. Drove me nuts for several months.
One of he plastic streamlining panels under the car had come loose. They are only held in place with plastic snaps that die with age. The one under the passenger side seat was flapping in the wind on the trailing edge.. Tied it up with a zip tie and the rumble is gone. It was silent at speed because the wind under the car held it up.

 

Hah, I wish. I'm intimate with my panels. I'll look again, but this is very much a rough road rumble/thudding, and it's not just noise, it's a rough ride. Completely absent on good tar.

 

@LexusMobilMechanic now you got me questioning my shocks... Turns out they're about 1.5 years old. Unfortunately shocks can no longer be shipped to the US, otherwise I'd buy new OEM from Impex or the website you mentioned. Just wish it was easier to narrow down what needs replacing.

 

These cars are super easy to work on - you just need a lift and see what is going on For replacement struts use KYB Excel - G Gas Strut… As mentioned earlier until you take a look under the car you are just guessing…. This should always be your 1st point of entry - then if you get stuck ask on here with picture's… Good luck

 

As I said, I've already done that (I have wooden cribs I use to lift the car and move around under it). I moved the wheels around, also looked at the bushings, although it really doesn't tell you much. I don't see anything out of the ordinary.

My replacement struts are Excel G. I've done some work on this car as well as on my LX470, but I just don't know how I'd differentiate LCA, UCA, LBJ, struts, strut mounts as the source of the noise. I'm fine with getting parts and taking it apart, I'm NOT fine with just buying all the dang parts to try to solve the problem.

 

Ask for replacement the struts - see if that does the trick since you ruled out bushings mounts and other parts…

 

If it's noisier over roads that are less smooth it sounds like tyre noise to me.
I used to have AVON ZV-5s on my LS which were nice and quiet but no longer available.
I replaced them with Goodyear Eagle F1 Asym3 and they are quiet but on certain road surfaces they are noisy as ****, especially on rippled concrete surfaces.