FB2k

My parents have a 99 RX300 AWD since new, currently it has about 98,000 miles and it has been properly maintained. But something weird occurred three times in the last two weeks... On a cold start (parked outside for approx. 3-4 hour after driven it), a whirling sound comes out from under the hood (it kind of sounded like an electric RC car), the sound speed up and slows down as the car speed up and slow down, but the car runs and shifts smoothly the entire time, no check engine light of any kind. While the car is in the park position, I slowly press down the gas pedal and there is no whirling sound at all. If I continue to drive it with the sound, it goes away after 10-15 minutes of driving.

The Lexus dealership can't make out what that sound is from, and since its not currently doing it, they can't diagnose it. I've attached a YouTube video of the sound recorded on an iPhone, hopefully someone in this forum had a similar experience and can tell me whats wrong with the RX. Thanks so much in advance!

http://www.youtube.com/watch?v=-jsClsFvhXw

Lexmex

Welcome to the Club.

That's tough to tell. Whenever I get noises like what you are describing, I take a look at my air intake (it's heavily modified), but it will make certain sounds on certain days depending upon the weather (temperature).

I'd check the black airbox in the engine compartment, open the top and see the condition of the air filter there). That filter may be plugged up and the engine may be having to suck harder to get at the air.

The only other thing is to have someone outside the vehicle see if they can hear the engine sound. If you were on abandoned road late at night it may be possible to open the hood and drive slowly (looking out your window to look forward) and an observer may be able to pinpoint sound better.

THERE'S ONE MORE POSSIBILITY.

Take a look underneath your engine at the exhaust piping and you should see a little area directly underneath center that is an accordion-like piece,




That piping can go bad and can cause a whistle or whirring kind of sound.

salimshah

Why dont you pop the hood and record the sound.

If it happens on cold (not warmed up) it can be one of the two belts. Next could be the air cleaner cover ... see if the clips are secured all the way.

Still staying with the cold ... watch the temp gauge and if you deduce that at a certain temp the noise goes away, then the culprit could be the coolant thermostat or water-pump.

As code said, open the hood and use your ear-***** to find the source of the sound.

Salim

FB2k

Hi Lexmex,
Thank you so much for those suggestions, I'll take a look at them this weekend when I go see my folks. But I'm thinking its possibly some other cause because the sound goes away on its own every time while driving, and it does not make the sound when the RX is stationary while I rev up the engine. The sound is very pronounced, much louder than what the video indicates, and the frequency of the whirling and loudness increases with the speed. The sound fluctuates in the video is because i was accelerating and lifting.

I just hope its not (but I think it just might be) the dreaded transmission failure issue, as its within that mileage window, even the fluids have been changed 3X since new. It really kind of sucks

FB2k

Hi salimshah,
I'm pretty certain, its not the belts or exhaust leak, because just have them all changed like 6 month ago, and the fact that the RX doesn't make the sound when its stationary while I rev up the engine. It only happened 3 times so far, and its been fine now for 4 days without any weird sounds, so I would have to wait for it happen again in order to check the cause, not sure what is triggering it, except in 2 of the instances, I had driven the RX on 50+ mile trips, climbing some pretty steep hills on the highway.

Cruiter

My previous '03 made a very similar sound as yours but not after it had been parked. It was after driving in very intensive rain around the city. It would soon go away and never bother me again till I got into a lot of water. I attributed it to wet belts. But yours might be a different situation. Could it be a power steering leak ???

FB2k

Hi Cruiter,
I'll check for leaks this weekend, but it doesn't really explain why it's not making any sound now if its still leaking.