I'm currently experiencing a loud rattle/knocking noise coming from my front passengers side wheel area. I have a 2005 RX330 with 186k miles. The noise sounds like it's metal to metal contact. It occurs when driving over the slightest of bumps or uneven pavement. It's a constant noise when driving under 30 mph but seems to disappear when traveling at freeway speeds. Additionally, my TPMS light comes on after about 20 mins of driving although the psi in all 4 tires are fine.


Any ideas of how I can diagnose the problem?

Thanks!

 

I would jack up that wheel, and hand spin it, see if you can reproduce the noise. I am guessing you can, cuz it's a constant noise. If you take the wheel off, it might be easier to locate the source.

 

Could be wheel bearing hub, agreed get the wheel off the ground, spin it and go from there.

 

Thank you both for your suggestions. I thought I'd post how I resolved the issue in case it might help others in the future.

I spent some time trying to track down what was causing the noise. I removed the wheel and plastic covers underneath and inspected every suspension part and motor mount I could find by prying, banging on, rocking, etc. Everything visually looked good and no abnormal movement at any joints. I decided that since my RX330 has 186k miles on the original struts, it would be a good starting point and hopefully solve the problem. I replaced the entire front strut assembly on both sides as well as both stabilizer links. I went with FCS Strut Assemblies from Rock Auto. This is a complete (strut, spring, mount, bearing, etc) assembly making it an easy swap. This is a great DIY job even for the beginner. You can find a great video tutorial on YouTube if you search "Highlander Front Strut Replacement". The job is done on a Highlander but the process is pretty much identical for 2nd gen RX330's. The noise is gone and my RX drives so much better. It's amazing how much of a difference new struts can make.

 

I had a noticeable rattle a while back and it was due to the small metal holding the exhaust in the middle broke off. My mechanic welded it back on. That solved one of the rattles I had. The other was from my driver front wheel side. Had to replace the link.