BayAreaLex

Hi guys,

I’ve noticed a subtle problem with my 2001 GS430 that I am hoping you can help me isolate (the car has 115K miles). The problem has been present for at least a few thousand miles.

Under light acceleration/load, I can hear a high pitched chirping coming from the engine bay. If I let off the gas a little, the noise goes away. If I press the gas more aggressively, the noise also goes away. It seems to be present only under light load. The vehicle speed or which gear the transmission is in doesn’t seem to influence it in any way.

It makes me think that it could be serpentine belt/tensioner/crank pulley/alternator related, but I’m not sure yet. I’ll have to get in there and investigate further but wondering if you guys may have encountered anything like this?

Although I haven’t tried it, I will see if I can reproduce the chirping noise with the hood open and the car in park (while revving the engine and seeing if I can isolate it). Also, I may see if there is any influence by having the AC on or off.

Thanks guys!

2GSKaizen

iTrader: (1)

If you can isolate it to a certain rpm range I would def think it's something on the accessory drive seeing how speed or gear doesn't influence it. Maybe see if you can post a video?

tmf2004

iTrader: (15)

i'm guess one of your pullies or the tensioner.. the bearings could be bad and make a noise under acceleration

D3V3LOP3R

iTrader: (3)

Mine was doing the same, turned out to be the tensioner pulley...pretty easy DIY, if that's what it turns out to be.

BayAreaLex

Thanks guys. If it turns out to be a tensioner pulley, does anyone have a Lexus part# available?

tmf2004

iTrader: (15)

i bought mine from Rock Auto..

BayAreaLex

Did you go with Goodyear or some other brand?

tmf2004

iTrader: (15)

goodyear belt
goodyear tensioner pulley
gates idler pulley

BayAreaLex

Hi guys, just an update on this.

I haven't had a chance to find the culprit but what I did find is the chirping only happens at a very narrow RPM range of 2100RPM (+/- 50RPM) in any gear. Yes, that narrow! If it's below 2050 or above 2150 or so, there is no noise.

Does that sound like a pulley?

wbmx1981

Could be the pulleys as already mentioned or it could be something as simple as the drive belt.

tmf2004

iTrader: (15)

pop the hood and have someone press the gas pedal in park and raise the RPM's to 2k slowly and listen by the pulleys and let and see if thats the culprit... probably idler pulley

BayAreaLex

Update:

The 2100RPM chirping is only occurring when the car is moving (i.e. under light load).

If I just rev the engine with no load, there is no chirping. That makes things harder...

RichS11

I had this and it got worse over time. Sadly it gave out on my old GS300 and the belt fell off on the motorway. Thankfully I pulled over quick and shut the engine off so I never overheated anything. Mine never got really loud, hence why I didn't rush to change it and it sounds like the symptoms you're getting.

I'm not saying it is your tensioner pulley, but just keep an eye and ear on it if it gets worse.

maxx430

Try to spray some belt dresser on the serpentine belt and see if that fix the noise. I had a similar issue and after replacing the pulley and tensioner, it was the belt.

BayAreaLex

Hi guys, just to update this post:

I went ahead and replaced the serpentine belt. Problem persists.

I just ordered a replacement tensioner and idler pulley. Will report back soon.

Thanks.