Oivey2000

'03 RX300, close to 70K miles. suddenly developed this strange rattle which sounds like it's coming from under the driver's side hood/dash. totally sounds like it's something that is "loose" and it rattles/vibrates with each bump in the road; however, goes away once the car is warm! after the car sits awhile, same thing. i checked under the hood around that area & can't see anything that might be loose. had a mechanic check it out & of course it didn't make the noise for them, but they thought it might be a heat shield which was loose & i was hearing the vibration untl the car warmed (sounded plausible to me) , but it wasn't loose. it's very disconcerting in the mornings and anytime the car has sat & cooled. it's sounds like it's coming directly from under the dash or something under the hood on the driver's side. anyone ever experience anything like this?

sktn77a

iTrader: (2)

Heat shields usually vibrate/buzz more than rattle and in conjunction with engine speed rather than bumps; is that what it sounds like? You probably need to better locate the source of the noise to get help here - inside the car (dashboard) or outside/under the car?

tomstep2

I have the same issue with my RX. Both the dealer and my other mechanic advise that it is the front strut mounts. When it is warm outside, or the car heats up, the noise seems to go away.

I would have your front strut mounts checked.

carguy07

Mine does the exact same thing too. I was getting ready to post this but figured I would get a bunch of "look for something loose" answers. Drives me nuts. Think strut mounts would be covered under CPO warranty?

OleBob

I bought my RX300 new in 2000. In the last few years it developed a rattled in the front left side. It occurred when I would hit a dip or bump in the road. I could not tell if it was the suspension or in the dash. Due to the age of the vehicle, I replaced all four struts and link arms. That did not fix it.

Drilling into other threads I found the second generation, the RX330, had problems with the HVAC ducting becoming loose and rattling around. I stuck my hand up under the dash just right of the steering wheel and at the top I found my defrost vent trunk was loose. I pressed it up and resolved the issue for awhile. I think the trunk is held in place with plastic plugs because after a few more days of bumps, the noise came back.

Being of sound mind and infinite time, I fixed the problem for now without taking the dash out. My solution was a thin sheet of foam I positioned under the loose end of trunk. I folded it and wedged it under the trunk in a narrow cavity to keep constant pressure on it.

Very nice and quiet and the ride is like new with the new struts.

Next project: rebuilt door lock actuator.

OleBob

Djpoint

i too have been experiencing that rattle. It definitely is the defrost duct work. I wedged an old empty cassette tape case between the plastic duct work and metal frame. Problem solved😉