Belt squeal! Need expert advice.
12-01-08, 02:11 AM
#32
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Its been snowing all day. The new belt i threw on got louder since it got frigid outside. Discovered that it is most likely slipping on the hydraulic fan pulley.
Is there a way to bleed the hydraulic system, or change out all the fluid, etc? I think the hydraulic fan pump is not turning very freely at full rpm. Fan doesn't turn very fast.
Is there a way to bleed the hydraulic system, or change out all the fluid, etc? I think the hydraulic fan pump is not turning very freely at full rpm. Fan doesn't turn very fast.
12-01-08, 02:46 PM
#33
If your automatic belt tensioner is weak, it will let the belt slip under a load and fry the belt. My 400 has 3 marks on 1 piece of the tensioner and a pointer on the other part, as long as the pointer is between the 3 marks I think its OK .
12-01-08, 02:57 PM
#34
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yeah, check that tensioner. That internal spring weakens over time thus not keeping your drive belt at the proper tension. That could be your culprit.It is not a difficult DIY on a SC300.
12-02-08, 06:36 AM
#35
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the arrow stays in between the 3 tick marks on mine. when the engine is off, its at the middle mark, when its running, it doesn't move more than half a tick mark in either direction. Also my tentioner spring is very strong.
12-02-08, 08:49 AM
#36
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Shaar, I feel your pain. I had these same issues with my first SC (92 SC300). FIRST, did you check the Harmonic Balancer as stated in my earlier post? Did you do the procedure with the thin/narrow paint line across the complete face of the main crank pulley? You MUST confirm that your Harmonic Balancer is not beginning to seperate. Your screaching noise is caused (MOST LIKELY) from a belt that is not as tight as it needs to be, OR is slipping some how. Can we all agreed with that!....? A weak tensioner pulley will do this(as well as a Harmonic Balancer going bad) and after REPEATED belt installes will weaken the tensioner pulley spring even more. I would just put on a new tensioner pulley on and be done with it, REGARLESS of what the markings indicate. (This takes care of one of the variables).Sell your old one on Ebay if you still believe it to be in good shape (probably not). Also make darn sure your pulley grooves are brushed clean and your belt install is centered on all the pulley grooves (alternator/main pulley/power steering pulley) Because you shreaded a new belt (tight belts do not slip and shread) my money is on the Harmonic Balancer or the tensioner pulley or perhaps BOTH. BTW, humidity (I live in Houston) will cause the belt to slip just a bit(screach) till the engine warns up and burns off the moisture.I have been there Shaar and these two things (at two different times were my causes, tensioner and Harmonic balancer. Good luck,Keep us updated
12-09-08, 08:18 AM
#37
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I think i found where the squealing is occuring. I figured I'd change my oil yesterday and poke around under my car for a bit. Seems that the belt is sitting crooked on the hydraulic fan pulley. This is a flat pulley and from the angle of misalignment, the wear on the belt matches exactly.
There is nothing that i can think of that has changed since i bought the car to cause this belt to be misaligned and not turn the pulley effectively. I bought it in the summer, and now its winter, so the only thing i can think is that the fluid in the hydraulic fan system is either too thick (the guy i bought this car from didn't know what he was doing with this car), but in the summer its hot and doesn't restrict the pulley as much. Or something is happening with my crank pulley (coming apart). I looked over the crank pulley and see nothing obvious. It also doesn't have any play when forcefully trying to move it. So i'm at a loss. Is there a thinner fluid i can put in the hydraulic fan system?
Here is a detailed drawing showing the hydraulic fan pulley and my misalignment problem. Thanks MS Paint.
There is nothing that i can think of that has changed since i bought the car to cause this belt to be misaligned and not turn the pulley effectively. I bought it in the summer, and now its winter, so the only thing i can think is that the fluid in the hydraulic fan system is either too thick (the guy i bought this car from didn't know what he was doing with this car), but in the summer its hot and doesn't restrict the pulley as much. Or something is happening with my crank pulley (coming apart). I looked over the crank pulley and see nothing obvious. It also doesn't have any play when forcefully trying to move it. So i'm at a loss. Is there a thinner fluid i can put in the hydraulic fan system?
Here is a detailed drawing showing the hydraulic fan pulley and my misalignment problem. Thanks MS Paint.
12-09-08, 09:39 AM
#38
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The pulley probably got worn down with time. I wouldn't really change the fluid in the hydralic fan because if you put a thicker fluid in it you risK the chance of seizing the bearing inside of it. Replace the pulley or you can get rid of it totally and not worry about it by buying the LS400 fan bracket. You use the same belt just by the bracket and the fan that comes with it. Or you can just get the bracket and have your own custom electric fan setup.
Last edited by SHOLEXMAN; 12-09-08 at 03:16 PM.
12-09-08, 01:43 PM
#39
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did you paint a THIN straight white line across the whole face of your harmonic balancer to CONFIRM it is not separating or splitting apart? Takes one minute. Yes or No?
12-09-08, 04:13 PM
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WITHOUT a line mark, a quick look at the harmonic balancer will mostly reveal nothing to you. Paint a straight thin white line (this color is easy to see) radiating out from the center (mounting bolt) to the outer lip of the main pulley. The main pulley (Harmonic Balancer) is fused together with hard rubber somewhere in the middle of the face of the pulley(the pulley is actually made of two parts fused together with rubber)That is why it's called a "Harmonic Balancer".. Paint the straight white line, then go for a spirited little drive. Come back and shut the car down and look to see if you still have a perfectly straight line of paint across the pulley face. If you harmonic balancer is split, you will have a "broken" straight line (2 lines instead of one).A split Harmonic Balancer will DIFFINITY cause a screeching/slipping belt. Good luck and let us no where the problem lies.
12-10-08, 08:01 AM
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Oh, i forgot to make it clear that the pulley isn't worn down, the belt sits crooked on the pulley. I tried drawing it acurately to show how the belt sits on the pulley. The brown area is where the original black paint on the pulley is worn in a straight pattern, and the belt doesn't sit straight anymore.
12-10-08, 08:04 AM
#45
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Also figured i should remention i have an SC400 and not an SC300. But i will determine if the harmonic balancer is the culprit in a few days. From what i read, if it is my problem, its a bear to change out... sigh.