tahmadov

My father-in-law's 2001 Lexus RX300 makes squealing/whistling sound when engine is cold. Multiple serpentine belts replacements and adjustments made no difference. One mechanic said it's the bearing inside the alternator, but I find it difficult to believe. Why would bearing sound go away when it heats up? Besides, I've never ever heard of or seen anyone having issues with bearings inside things like alternators and such.

salimshah

Have you tried it without the accessory belt? There are other belts ,,, power-steering and timing belt with its drive train and can produce a squeal.

Was a belt tension gauge used or old technique of twist the belt? There is substantial difference in new installation and with 10 minutes use.

If the belt slips for a while, it develops a glaze and can become unusable as it looses the softness and even with proper tension it slips.

All belts are not equal and production quality has gone down in the game of providing the cheapest.

As far as alternator bearings are concerned, their life expectancy depends upon the belt not beeing too tight.

You can use a spray bottle and give the belt a mild sweat and see if the whining goes away.

Salim

carguy07

Are you using an OE belts or aftermarket?

tahmadov

Thanks for the reply!

I'll double check but I'm pretty sure both have been replaced twice.
It's a good idea to try running for a short while without each belt to localize the problem.

Will check on this. He did have it re-tightened after installation, but I doubt it was installed loose. All work was done by mechanics...

We did use aftermarket belts, but the price wasn't too different from dealer price, I think it was within the dealer markup difference range.

Which ironically means tightening the belt too much will make this problem worse, not better Are rebuilt and brand new aftermarket alternators OK quality usually, or are dealer parts recommended?

You can use a spray bottle and give the belt a mild sweat and see if the whining goes away.

Salim[/QUOTE]

trips1

Reviving this old thread as i am running into the same/similar problem.
Tried using the HF auto stethoscope but still not able to narrow down the area of noise as the overall car itself has become little noisy after 15 years :-)
At a high level it appears to be coming from the alternator area or from somewhere within the engine below the top "Lexus" panel. I am having difficulty in catching the exact area with the stethoscope.

The noise becomes almost 75% more pronounced when i put it in the Reverse gear. Lasts for total 3-4 minutes and then becomes normal. Will upload the video and see if i can get some possible recommendations.
I also took it to the mechanic and they unnecessarily changed the belts even though i had done all the tests to ensure that the noise is not because of the belts.

And one general question.
-If the noise is from the alternator bearings becoming dry and going bad, what is the worst that can happen if i leave it like that for extended period of time? As of now i don't notice any other problem with the car at all, other than the morning 3-4 minutes of noise.

Thanks,
Trips

Drcoffee

So I use a quick and reliable trick to isolate the squeal noise of the pulley area. Start the engine and one at a time, spray the pulley bearing of each pulley With WD40. Not the pulley or the belt, but the shaft the bearing is on. If it quiets down, you found the culprit. Wd40 will not hurt anything and its a thin oil that can go only where water can go. If none of the bearings quiet down you can then spray the pulley side of the belt.

bearings do go bad on alternators over time and then they seize throwing the belt and causing all sorts of problems. Its normal wear and tear and it can happen to all cars. Its nothing unique the Lexus. I just replaced mine because the voltage regulator failed. You can buy a TYC brand new for $111 shipped from rockauto.com.

salimshah

Pulley noise does not typically go away after few minutes.

If you have not replaced the belt in last 3-4 years then simply replace the belt and see. That belt needs replacement in any case.


Belt noise can't be 'scoped ... the nearing noise can be confirmed with 'scope.

Also timing belt and it train can cause noise as well.

Salim

RX469

iTrader: (1)

I'll chime in as I'm experiencing the same.....
I have new OEM belts and was starting to think my squeaking are from the drive pulleys and was contemplating changing them?

I'll keep trying to diagnose and continue updating this thread.

trips1

Thanks Drcoffee. I will try this out. So essentially i should spray at the center bolt(shaft) that goes through the pulley all the way through the center?

The mechanic changed the 2 belts even though i was sure based on experiments with water spray that the noise is not from the belts. My old Mitsubishi belts were only 3.5 years old with 25k miles. I could not say no to the mechanic as he was too positive on the phone that the noise is because of the belt.Now i have bando belts instead of my Toyota Mitsubishi belts
Anyways i am asked to drop off the car again, but not too confident that the mechanic will be able to do a good job.

Salim, any information to figure out if the noise is from the timing belt? At this time i have 150K and at around 70K the car had gone through a major Lexus paid repair for the oil sludge in 2005 and the lexus invoice indicated that they also changed the timing belt. May be i am too paranoid but i am not certain if they actually changed it or not. I would think that if someone has to get in to check the timing belt then it would be as good as getting the timing belt changed by paying little extra.

Thanks,
Trips

Drcoffee

Whatever it takes to get the lube in the bearing.

salimshah

The timing belt itself is very unlikely to make a noise, but the idlers (lubed for life) can squeal. I replace them with every T let change. Once the lube runs out, the idlers start changing color to blue-shade due to heat buildup.

Start by a thorough examination of the main pulley. They can develop a crack.

You can ask your mechanic to just remove the alternator-ac belt and run the engine. If there is no noise then it the belt or tension , or the alternator or the AC-clutch.
If there is noise then take the steering pump belt off and run the engine. If there no noise then it the steering pump or tension or the belt.

If you still have the noise then it time to open up the T- belt cover and see the condition of all the components including the water-pump.

Salim


I would first eliminate the squeal from accessory and steering pump and then go after the T-belt train. You can remove the external belts and run the engine. If the noise is there then it is the T belt train.

trips1

Thanks Salim for your inputs!
Since the noise is there only for 3-4 minutes i would need to do these experiments on different days or 5-6 hours apart. Based on all the valuable information on this forum i have understanding of the alternator and the PS belt and i can also do it myself if it becomes necessary..
Would you or others be able to comment on how much approx money i would need to shell out to a mechanic just to get the timing belt train and the water pump checked.

trips1

So the mechanic has determined that the noise is coming from the transmission and as per him he is 100% positive about it
As of now I have not observed any issues in automatic shifting of the gears even though noise has been there for last 4-5 weeks.
As i had also posted above that the noise becomes almost 75% more pronounced when i put it in the Reverse gear. Lasts for total 3-4 minutes and then becomes normal.

I have been changing the ATF as well as the pan/filter regularly. The last ATF/pan/filter change was in October 2014.
I am planning to do the full DIY once again, though the parts will arrive only early next week.

So hoping to get some further feedback from the experienced folks here.
1- Any way for me to personally determine at home that the noise is coming from the transmission? Any specific place i can put the auto stethoscope and try to listen to the noise that becomes more pronounced when putting in reverse gear.
2- Anything more that i can do in addition to the ATF pan/filter/fluid change. From the information on this forum the use of ATF additives is somewhat discouraged.

I would essentially need to continue to drive the car till early next week when the parts will arrive. Hoping that it does not become catastrophic for the transmission.

salimshah

I am lost.

With transmission in Park or neutral .. you never get a squealing noise? I have been under the impression that the noise is in Park .. that is how you isolate the transmission.

Before we go down the path of transmission ... please have the engine mounts and suspension examined.

Salim

trips1

Hi Salim, let me summarize the whole thing to give a clear picture.

- Note that the noise goes away after 4-5 minutes in all the scenario's.
- When i start the car i the morning or late evening after car has been in the parking lot for 8 hours there is a whistling/squealing noise. The noise increases by about 75% when i put the car in reverse gear. I do feel little extra resistance in the hand when moving from P to R but that is how it has been forever.
- Today i tried to apply all the gears (P, R, N, D, 2, L) and the noise is indeed more prominent in Reverse gear and somewhat lesser in the P gear and then i felt the noise is lowest in 2 and L gear.
- When i have a helper start the car and move gear from P to R, I do observe the whole engine under the hood making a slight jerk/shift, though i really think even that might have been there forever because i remember feeling a very very slight jerk whenever i put the car in the Reverse to get it out of the garage.
- Mechanic has changed the belt and it did not help. I did try to put some WD-40 on the center of the alternator, but that did not help.
- Using the Harbor Freight auto stethoscope i am not able to concretely say where the noise is coming from. The alternator does change the noise a little bit when putting in reverse, but i am not very sure if the main noise is coming from the alternator.
- After checking further my auto mechanic mentioned that the noise is coming from the transmission and it would need a new transmission ($2500) very soon and that i can try to change just the ATF and see if it can help. When i questioned him a little more he reiterated that he is 100% positive about the noise coming from the transmission.

In any case i am planning to change the ATF as well as the pan/filter even though it was done only 22 months ago and have only driven about 14K miles.
If the noise still persists then i would have to take it to a local Lexus specialist and see what they have to say. The problem is that every time i have to leave the car overnight at the mechanic shop.

Based on the above description if anyone has any further pointers then please do let me know.
Any specific thing that i can personally check in the Engine Mount/suspensin or do i need to go to a specific specialty mechanic?
Also even if i assume the noise is from the Transmission, any specific area where i can put the auto stethoscope and hear the noise. If yes then a pointer to any picture on the web would be helpful.