Strange noise from the front of the motor - need help identifying it!

[virafp]

2001 LC, 186K, Timing belt done at 101K.

This is going to be tough to describe, but here goes:

On start up, there is a low pitched whirring sound, coming from the front of the motor. The noise increases with an increase in engine revs. It normally lasts for 4-5 minutes, and then goes away. It does not happen on every startup, I would say it occurs once in 3-4 days. Once in a while, when there is the whirring noise, the tach needle jumps up to 3.5K, without the same increase in actual engine RPM's. This was mentioned to me by my wife yesterday, but given that she has a bit of a lead foot, it could easily mean that she is giving teh car some gas to get moving in a hurry!

I replaced the serpentine belt, but the noise was happening before, so was clearly unrelated. It does not change when the car is in Park or Drive, so appears to be unrelated to the transmission.

Any help would be appreciated.

Thanks

 

[ENGINE er]

you need to invest in a stethoscope and start hunting accessory pulley bearings.

i just did my idler, tensioner and fan bracket pulley and my engine is MUCH quieter. They had all gone bad.

 

[OregonLC]

You sure it's to the fan clutch? Sometimes those take a few minutes to loosen up.

 

[virafp]

Can these wait till I do the timinb belt

I was going to do the timing belt in 10K miles, so these will get done then.

When I di the TB at 100K, the following was replaced:

Timing Belt
TB Idler Bearing
TB Tensioner Bearing
Water Pump
Front Engine Oil Seal
Thermostat

Plan on doing the same change outs again. My SA at Toyota who is very good, says I can go an easy 100K so I am not due for another 15K. I plan on doing it in 10K.

Maybe I will find a sthetescope and start to dig around.

you need to invest in a stethoscope and start hunting accessory pulley bearings.

i just did my idler, tensioner and fan bracket pulley and my engine is MUCH quieter. They had all gone bad.

 

[virafp]

Fan Clutch

This was my first guess. How do you test the fan clutch to see if it needs to be replaced? The fan functions OK, and the car does not heat up at all.

How should the fan operate? When the engine is cold, it normally spins up at high RPM, and settles back down. On a cold engine with no AC on, should it even be moving at all after the initial movement? I think mine stays on all the time.

You sure it's to the fan clutch? Sometimes those take a few minutes to loosen up.

 

[OregonLC]

This was my first guess. How do you test the fan clutch to see if it needs to be replaced? The fan functions OK, and the car does not heat up at all.

How should the fan operate? When the engine is cold, it normally spins up at high RPM, and settles back down. On a cold engine with no AC on, should it even be moving at all after the initial movement? I think mine stays on all the time.

The fan clutch uses something like a bimetal strip to cause it to engage at high temperatures and partially disengage at lower temps. I say partially because there's significant drag from the fluid in the housing causing the fan to spin at all times. When it's not engaged it's quiet, when it's engaged you can definitely hear the roar when it's at full speed. They engage at start up briefly due to fluid drainage. Link: http://www.offroaders.com/tech/fan-clutch.htm

 

[Copenhagen1]

........ start up, there is a low pitched whirring sound, ........

Viraf I know this sounds like a dumb question but is there any chance you are hearing the ABS pump that is located at the brake master cylinder? I know you said the front of the engine but when I read "whirring sound" and also that it doesn't happen every time upon startup, it made me think of the ABS pump.

Also, I just did my 180k timing belt. I purchased brand new OEM parts for almost every part that got touched. I figured my idler pulleys and tensioners and everything else had 180k miles on them and I plan on putting another 100k on the truck. I even replaced the fan clutch and the bracket it rides on. Let me know if you need an extensive list of part #'s for this 2nd timing belt service. If it turns out that you need a fan clutch, I have a used one with 180,000 miles on it that I could send your way.

Sent from my iPhone using IH8MUD

 

[lhfungo]

I would like to know the outcome from the OP. I noticed a new noise this morning when I started my '04 and walked around the front of the vehicle. The noise level was relative to the RPM speed and went away after 2 minutes of warm up.

 

[lhfungo]

Paranoia sent me to my vehicle at lunch. Started it up from the passenger side, just like I did this morning, and that whirring sound was there. It's not overbearing and I'm wondering if it has been there all along. I rarely reach across the passenger seat to start it up so maybe I'm a little sensitive to what I heard today. I did pop the hood both times to stick my ear into the engine compartment and with great confidence I can say that the whirring sound is coming from the front passenger side of the engine.

 

[ton504]

Your powersteering pump and alternator is there. Hows the p/s fluid level?

 

[virafp]

The noise got a bit worse over time, so I just decided to let it go till it could be diagnosed. So about 16 months later the alternator went out...and surprise, new alternator = no more noise!

 

[SmoothLC]

I would like to know the outcome from the OP. I noticed a new noise this morning when I started my '04 and walked around the front of the vehicle. The noise level was relative to the RPM speed and went away after 2 minutes of warm up.

I've had a noise in the front of my LC for a couple months. Took it over to a friend of mine (former Toyota master tech.) last week. Pulled out the stethoscope and in a few minutes determined it was the serpentine belt tensioner. Took off the belt to confirm and ordered a new one from Beno/Onur. Now just need to get it installed.

 

[BamaHeel]

After a period of thinking that it was my power steering pump I figured out it was the serpentine belt tensioner. Easy fix.