Adam200699

I have a 2005 RX 330 with 198,000 miles. A few weeks ago, after I replace the battery(may not be related), I noticed a strange noise (sometimes very loud) from the bottom the vehicle. When I put the car in drive, and idle at red light. The idle speed is around 600 RPM, and the car runs fine. I can feel a vibration on the steering wheel, and metal tapping noise from bottom of the car. When I apply a little bit of throttle, the noise goes away. Sometime I shift to Neutral, or Neutral to Drive, or turn the AC on and off, the noise also goes away for a few seconds. When I put the car in Park, the noise also goes away. It does not happens all the time. It happens more often in stop and go traffic, and go up incline hill.

Recent work done on the vehicle, Timing belt, water pump, PCV valve replace about one year ago.

I did try a few things on my own. 1. Clean the throttle body, 2. Techron fuel injector cleaner. no effect.

All the Engine mounts looks OK. All the heat shields on exhaust looks fine, there's no loose part.

Here's the problem. When I take the car to my local mechanic, and I can not duplicate the noise. I put the car in idle for 10 mins, and nothing happen. When the noise come back, and only lasted about 10-20 seconds. Not enough time to locate the noise. It's coming from the general area around the front of the engine, catalytic converter.

Any idea? I'm in the process of deciding should I keep the vehicle for a few more years, or move on.

Adam200699

I made a quick video. Scan tool shows no error code, and the car runs fine. You can hear in the video the noise went away at 20 seconds, then come back a few seconds later. Any input would be appropriated.

mnewxcv

Sounds to me like an exhaust heat shield. Check around the cats. Take a metal object and apply pressure to the heat shields when this happens to see if the sound changes or goes away.

h2iskibum1

Check heat shields near cats