satiger

iTrader: (1)

My ES is closer to 250k.

It started emitting a humming noise (under the hood - more precisely on passenger side) about a month back. Two weeks prior to that I had both front shocks replaced with after market one.

I hear the humming sound when I start the car (not in motion) and on any lever (park, drive, reverse etc) position. When in motion I don't hear, may be due to other road noise - not sure.

This is driving me crazy. When I open the hood, I could feel it is coming from passenger side closer to the firewall.

I recorded it posted in youtube : . Recorded using mobile phone, might want to increase the speaker volume to listen to the humming sound.

What is causing this?. How to fix it?. Any suggestions....?

ES300NZ

it sounds like it's in the transmission to me, more so as the sound changes alot when you move through the gears.

- I'd have that transmission flushed asap.

satiger

iTrader: (1)

Thanks ES300NZ for the quick response. I will have transmission checked immediately.

I am not sure if this leads to any clue - I hear this humming sound very clearly when I sit inside, not when standing outside next to the hood (bonnet)!. This is driving me crazy.....

ES300NZ

it could also be an accessory belt that's too tight. say alternator, or AC.

speedkar9

You could try eliminating a few things yourself before taking it into the shop.

First, check the transmission fluid, when warm. The level should be at HOT with the car on in Park, and the color should be red. If its brown or black, it needs to be changed.

Next, jackup and support the car from the front so the front wheels are in the air. Chock the back wheels so the car doesn't move. Run through the gears and let the wheels spin (to eliminate the road noise) to see if the noise is speed or RPM dependent, or just an occurrence at idle.

Then remove the alternator belt, and power steering belt. If the noise disappears you can narrow it down to a bad power steering pump bearing or alternator or A/C bearing, or the belt was on too tight.

If the noise is coming from the right side of the motor with the belts off, its probably something under the timing belt cover, like a water pump or idler bearing.

I also noticed your HVAC fan was running...if you turn it off does the noise go away? Especially since you hear the noise more inside the car and outside right near the firewall...

satiger

iTrader: (1)

Thanks everyone.

I will check pumps and belts along with transmission. I doubt it could be transmission as I did pan drop and fill service done about 10k miles back. It wont hurt checking. Fluids level is OK.

I will keep you posted.

jenga

As goofy as this sounds, these methods works as you need to refine how you listen to the noise as sound bounces all around in an engine compartment.

1) Take a section of hose, like a garden hose diameter about 3ft long, hold one end to your ear and take the other end and move around the engine in different spots(ac compressor, power steering pump, alternator, intake, etc) to listen for the noise this will help pin point the area. Just make sure to stay clear of the belts.

2) For bad bearing noises, use a wooden post (dowel about 1", 1x1 or even a 2x4) and put the it on the part you want listen to. Place your ear on the board...does not need to be on the end, can be along side. The wood conducts the noise.

3) Get a mechanical stethoscope instead of option 2. They are cheap.

http://www.harborfreight.com/mechani...ope-69913.html

Video for help.

Hayk

iTrader: (1)

Satiger, use this suggestion and listen to your alternator. I believe that's the source of your noise.

satiger

iTrader: (1)

Just to close the loop, the humming is from alternator bearing. I am in the process of replacing that. Thanks for all the help and pointers.

RusM

I'm having the same problem. I hear it mostly when I park.the car. Sometimes I hear it when the AC is on. I have listened around the engine to find where it's coming from. The air intake trembles (I'm assuming from this noise) and I followed the air intake up to the top of the engine where there is more plastic. That also seems to have noise coming from it.