1995 LC squealing noise during idle (1 Viewer)

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Hey there guys, I've been trying to track down an extremely noisy squealing sound on my 80 series for quite some time now. I've pretty much narrowed down all my possible culprits and was wondering if anyone else can chime in here.


1995 FZJ80 w/ 237k miles

The issue I've been having for quite some time is during cold start, there is a horrendous squealing sound while idling. It is extremely loud and is a relatively high pitch as well. It is particularly loud when the temps are colder and the truck isn't warmed up yet. The noise is still definitely there, but is a little quieter once the truck is warmed up. One thing to note is that the noise almost completely disappears when you put the tranny into Drive. It makes the noise when you are idling in park and neutral, but not drive. The only time you can hear the noise while the truck is moving is when you are coasting to a stop and the RPMs drop back to idle.

Over the past 2 weeks I replaced quite a few of the parts that were looking worn and rough. These new parts include an OEM toyota thermostat, aisin water pump, aisin blue fan clutch, CSF 3-Row alumn radiator, and OEM drive belts.

I know the sound cannot be the water pump, clutch fan, belts, or idler pulleys. I know it cannot be the alternator idler pulley because I removed that completely roughly a week ago and did not put it back into place when I installed the new belts. The noise also cannot possibly be the lower AC idler pulley because there is currently no belt even attached to the AC compressor or the pulley. I am currently waiting on a new Denso compressor to come in so that I can replace that as well so the AC belt is currently not even installed. The reason I am replacing the AC compressor as well is because there was considerable wobble and a grinding noise when I spun it by hand with the belts removed. I thought the AC compressor was the culprit making all the noise, but it turns out it cannot possibly be the source of the noisy idle because the AC compressor is currently not even being driven by a belt. Also I inspected the alternator pulley with the belts off and there was no noise or wobble when spun freely.

I am beginning to suspect that the Harmonic balancer/damper is my noisy culprit. The fact that the noise only happens at idle and goes away when I put the truck in gear, thus changing the RPMs, makes me think the harmonic balancer is faulty. Also the trucks idle has become more and more rough over time, along with the noise getting louder and louder.

So with all the information I have gathered, can my fellow mudders confirm if the harmonic damper is indeed the suspect?

If the harmonic balancer is indeed the issue. Will I have to remove nearly everything that I just replaced(belts, fan, and rad) in order to replace that as well?

I am currently in the process of trying to upload a video so that all of you could listen to this wonderful noise at idle, but youtube keeps saying that an "error occurred", but I will upload the video asap.

Thanks for your time and thanks for the responses in advance!
 
Here's the video link:

 
Have you checked the torque on the big bolt that holds the crank pulley/harmonic balancer onto the crank? It is supposed to be set at 306 ft pounts. If it is loose, it can allow some internals to slip/spin on the crank.
 
Have you checked the torque on the big bolt that holds the crank pulley/harmonic balancer onto the crank? It is supposed to be set at 306 ft pounts. If it is loose, it can allow some internals to slip/spin on the crank.

I'll have to check it this weekend when I plan to pull everything apart again! I plan on pulling the harmonic balancer out to inspect it.
 
Have you checked the torque on the big bolt that holds the crank pulley/harmonic balancer onto the crank? It is supposed to be set at 306 ft pounts. If it is loose, it can allow some internals to slip/spin on the crank.
304 bro get it right
 
Unfortunately, there's no way to "check" the torque on that nut. You have to loosen it and then tighten it to verify the torque.

FWIW, if you try to turn the nut with a torque wrench, and it is tight, the observed torque will always exceed the torque you measure when tightening it during installation. Assuming, of course, the wrench is moving when the torque target is reached. It's the difference between static and dynamic torque that causes the problem.
 
Unfortunately, there's no way to "check" the torque on that nut. You have to loosen it and then tighten it to verify the torque.

FWIW, if you try to turn the nut with a torque wrench, and it is tight, the observed torque will always exceed the torque you measure when tightening it during installation. Assuming, of course, the wrench is moving when the torque target is reached. It's the difference between static and dynamic torque that causes the problem.
I forget the size of that nut but I suspect it'll take *more* than 304 ft lbs. When i tightened mine I just reefed on it with a 24" breaker bar to the best of my ability. Not ideal but good enough for the life i live
 
I'll have to check it this weekend when I plan to pull everything apart again! I plan on pulling the harmonic balancer out to inspect it.

I would check the torque on it first. Can be done by only removing the windahe pan from underneath. If it is not anywhere close to spec it may allow the oil pump/power steering drive gear to slip on the crank. It is NOT keyed onto the crank, but it is only captured by that extreme amount of clamping force due to proper torque on the bolt. Easy to check without ripping out other parts.
 
Unfortunately, there's no way to "check" the torque on that nut. You have to loosen it and then tighten it to verify the torque.

FWIW, if you try to turn the nut with a torque wrench, and it is tight, the observed torque will always exceed the torque you measure when tightening it during installation. Assuming, of course, the wrench is moving when the torque target is reached. It's the difference between static and dynamic torque that causes the problem.

Thanks for the input, I plan on removing the balancer all together this weekend. I plan on using the "breaker bar/crank the car" method to get the nut off. Only thing is, I don't have a 300+ ft lb torque wrench to reassemble when I'm done. I think mine goes to like 175 lol I'll probably rent a torque wrench from the auto parts store.
 
Thanks for the input, I plan on removing the balancer all together this weekend. I plan on using the "breaker bar/crank the car" method to get the nut off. Only thing is, I don't have a 300+ ft lb torque wrench to reassemble when I'm done. I think mine goes to like 175 lol I'll probably rent a torque wrench from the auto parts store.
They won't have one, but you can get a 300 LB one from Harbor Freight for about $80
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$80 then apply 20% off coupon that is valid everyday on one item per day.
Just need a pic of it from innerwebbs and they scan it on checkout.
Then yo will have the biggest torque wrench on the block.
 
An easy way to track down noise makers is with an automotive stethoscope available thru tool companies or online. It works very well.
 
could anyone tell me off the top of their head what size the nut is for the crank bolt?
 
I couldn't find a 30MM in my area, so I bought and used a 1-3/16" six-point socket and it worked flawlessly. (3/4" drive)
 
There are a couple of inch-metric sizes that are so close they are practically equal. 30mm - 1 3/16" is one. 12mm - 7/16" is another. As a matter of fact, a 7/16-20 thread is exactly a 12x1.25, FWIW.
 
Didn't see you mention having replaced the idler pulley for the fan belts? Mine was making noise because some gorilla managed to get a set of belts up and over the top of the idler, routing them incorrectly and causing premature failure.

Just a thought...
 
I love blanketed comments like this. Of course you know. I also can rent one here.
I have searched every aftermarket auto parts store in our area and most had no idea that TW's even went that high. Also, my son works for oreillO'Re and they didn't have one in their system for rental.


So........:flipoff2::deadhorse::moon:
 
Dead Horse gives one last kick...
Maybe he meant "rent" one from Harbor Freight.
 

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