ntwrkguy1

I've got this strange whining noise coming from the engine compartment of my '03 430.

The minute I start the car, it starts. It's still there when I drive, and it doesn't really get any louder or quieter. It reminds me a LOT of a noise that my '86 Maxima made back in the day when it passed the 200k mile mark. That turned out to be a power steering pump. But when I had my tires rotated/balanced the other day, the tech asked me about "that pulley noise your car is making". I didn't think that pulleys necessarily made any noise.

Is there any way to test the power steering pump? The car still steers so effortlessly that I would be surprised if it were bad. I've lifted the hood and tried to figure out what exactly is making the noise, but haven't been too successful.

Just as an fyi -- the car has 150k on it. I did the timing belt and new plugs around the 110k mark. The alternator is original. And the car has had regular drain 'n fills on the transmission, and it isn't driven hard at all. I'm willing to bet that the power steering fluid might be original (I haven't changed it, and the original owner didn't give me a receipt for it). The car drives and shifts as well as it ever has.

Any thoughts?

AnimalB

Sounds like an alternator.

Does there noise intensify when you turn the steering wheel while parked?

ntwrkguy1

It doesn't seem to -- I just went outside and tested it.

The noise seems to rise a little bit when I drive. I just went out and had the battery and alternator checked at Auto Zone. They said there was a dead cell in the battery, but said the alternator was "working ok".

It is possible for the alternator to make noise and yet still be functioning ok?

97-SC300

iTrader: (17)

Yes could be a bearing in the alternator, also could be an idler pulley

GS4_Fiend

iTrader: (22)

post a video.

ntwrkguy1

It does sound like a bearing noise, and given that the alternator is original, that wouldn't shock me.



I'll post one in the morning -- hopefully it captures the sound accurately.

ntwrkguy1

Had to travel for work for a few days and am just getting back in town.

I shot a video but it is way too large to post. And the sound on the video makes it sound like the car is about to blow up, but it's not.

I took it to a local mechanic that I trust, and he said he could narrow it down between the alternator and the idler pulley. As both are original, I'm inclined to replace both of them, especially at 150k.

Any issues with using aftermarket parts on the idler pulley? I saw that Rock Auto had a decent price on their Gates idler pulley. I haven't priced the Lexus dealer yet on the part, but if RA wants $44 for the Gates one, I would imagine Lexus wants at least $125 for the Lexus one.

HerLexOhMy

Hello. You can use a stethoscope to test the noise. If you don't have one, then do a more economical test with a plastic bottle and a screwdriver. I cannot locate the video, but you
1. cut the bottom out of a gallon jug
2. get a screwdriver whose butt will fit the top without going thru it
3. place the butt end of a screwdriver at the mouth of the bottle
4. Now go thru the engine with the screwdriver tip.

The tip vibrates and the sound is amplified thru the bottle.

A lot of advice shows putting the screwdriver to your ear as you test. THIS IS VERY DANGEROUS. You could damage your ear, face, OR you could tap a moving part and damage the car.

Yri

Valuable information, especially the screwdriver-to-ear thing. To be honest, it sounds like a good method, but you're about 8 years too late. Thread was made in 2013... No worries though, just be happy this isn't the Bimmer forums! LOL