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A week ago I got the car to my mechanic to make some maintenance and that included the serpentine belt. My car is running 33K miles. I know it's still early for the belt to be replaced but It was worn out a bit and saw lots of cracks from the inside due to the very hot weather and dusty winds here. So I changed it.
After replacing it, a synchronized sound came on the moment I start the car. It can only be heard with the hood popped up at idle. I think it's there too while the car is running but can't be sure as it's not that loud to hear when driving.
The mechanic said the tensioner should be replaces too and I know it's recommended to replace it everytime the belt is replaced. But it was not available at that time. I'm a bit familiar with how the tensioner sound and behaves if it's worn out and this is not a tensioner sound. I ordered it anyway to change it. But in the meantime, I want your help in identifying the problem.
This sound was not there before replacing the belt.
I found a vid which has the same noise my car is making but less noisy. Here:
So if a belt was changed and nothing else, then its most likely one of the following. In terms of cheapest to most expensive, here's what I see. Keep in mind that by changing a belt, it most likely is a little stiffer, smaller and tighter through its entire cycle through the engine:
Pulleys I dont recall but I suspect there's 2, maybe three pulleys. These are "cheap" compared to others in the list.
Hydraulic tensioner - These last a good while (~100K or more).
Power Steering pulley - these too last long
AC Compressor - hope its not that pulley on the compressor
Alternator - I've had alternators go bad (bearings wear out) after changing belts.
This is where you need to find which one of these is the problem. If I was doing the work, I too agree with the mechanic that I would have changed the pulleys.
Report back and let us know what you find. GL.
Originally Posted by DevilsG37s
Hi,
A week ago I got the car to my mechanic to make some maintenance and that included the serpentine belt. My car is running 33K miles. I know it's still early for the belt to be replaced but It was worn out a bit and saw lots of cracks from the inside due to the very hot weather and dusty winds here. So I changed it.
After replacing it, a synchronized sound came on the moment I start the car. It can only be heard with the hood popped up at idle. I think it's there too while the car is running but can't be sure as it's not that loud to hear when driving.
The mechanic said the tensioner should be replaces too and I know it's recommended to replace it everytime the belt is replaced. But it was not available at that time. I'm a bit familiar with how the tensioner sound and behaves if it's worn out and this is not a tensioner sound. I ordered it anyway to change it. But in the meantime, I want your help in identifying the problem.
This sound was not there before replacing the belt.
I found a vid which has the same noise my car is making but less noisy. Here:
So if a belt was changed and nothing else, then its most likely one of the following. In terms of cheapest to most expensive, here's what I see. Keep in mind that by changing a belt, it most likely is a little stiffer, smaller and tighter through its entire cycle through the engine:
Pulleys I dont recall but I suspect there's 2, maybe three pulleys. These are "cheap" compared to others in the list.
Hydraulic tensioner - These last a good while (~100K or more).
Power Steering pulley - these too last long
AC Compressor - hope its not that pulley on the compressor
Alternator - I've had alternators go bad (bearings wear out) after changing belts.
This is where you need to find which one of these is the problem. If I was doing the work, I too agree with the mechanic that I would have changed the pulleys.
Report back and let us know what you find. GL.
Thanks for the info.
Some progress I made yesterday. I grabbed a small flexible tube and was carefully touching the pulleys center bolts with one end while the car is idling and the other end sticking into my ear (Homemade stethoscope) lol. Anyway, The ticking sound came very clear from the belt tensioner. Also while at it with a really bright flashlight, I saw the smooth idler pulley wobbling and it was clear.
Now I don't know what would cause all this but could it be a really tight belt?!
The belt in the link which is newly installed is within specs and designed to exact fit our cars.
So belt tensioner is determined by the deflection of the belt under pressure. If the tensioner was losing its tension and was not acting as designed, the belt would feel loose. I never realized the tensioner had marks as you indicate, so that is a GOOD sign its the proper tension.
If you want, you can look in the FSM for the amount of deflection (in cm?) based on the amount of force (in lbs?) to see if its in range. A lot of time you can tell by hand-pressure and deflecting the belt. Its a "feel" you acquire.
As for for the belt size, I'm sure you have the spec for this belt and that it matches the OEM specs. However over time the belt WILL stretch due to heat/forces/friction. Its only natural. The new belt could very well have created this condition due to be tighter than the stretched out belt you took off. I lost an alternator when I replaced a belt on a Toyota.
But the belt tensioner, I'm sure could be hydraulic and has a pulley. I suspect ALL of it needs to be replaced vs just the pulley on the tensioner. If you can replace this pulley on the tensioner, then that is the cheaper route.
Let us know how it goes and good use of the diagnostic tool to pinpoint the source of the problem. Sometimes that is the HARDEST part!
Originally Posted by DevilsG37s
I double checked everything. The belt path is correct and also the position on each pulley is ok.
I just need to know how to check the belt tension is ok?
In this picture you can see the tensioner mark right at the center that means the tension is ok. But how to make sure the belt isn't too tight?
Last edited by petemo94; 11-05-2015 at 06:12 PM.
Reason: added line
I tested the belt tension by pushing with a thump but it was very tight and pressed very hard to just move it down a tiny bit. I guess this is the issue. And what made this is a bad automatic tensioner because if the tensioner was working well after installing the new belt, it would automatically adapt to the tension of the new belt because that's its job.
My guess is that it's stuck on the old belt tension level and it can't loosen enough for the new tight belt. That's why there is a sound coming from it. With that being said, the tension of the belt plus the tension of the stuck tensioner made the pulleys to wobble and maybe they lost the bearings.
I will check them once I receive the parts. My shipment got lost or stolen from FedEx I don't know. The final delivery was delayed enough so I called them and they informed me that it's lost.. That was really disappointed. I filed a claim for compensation and now I'm waiting for the second order to arrive.
Does the tensioner pully rotate smoothly without and grinding or rough spots? Is there any play in the pulley. I don't hear any usual noise in your video, but that that's not saying much.
Received the new tensioner + the three idler pulleys. Replaced them and guess what, the sound and the wobbling was still there.
So I told the mechanic to install back the old belt which happened to be with me. Once installed, everything was so smooth without any noise and wobbling.
I decided to keep the stock tensioners and idler pulleys for later replacement because they're in good condition.
Note: If you happened to experience some minor wobbling in the idler pulleys while routine checking them by hand or belt replacement, it's normal and there is no need to worry. It's worrying only when it's wobbling while the car is running.
Advice: stay away from aftermarket belts and stick with the OEM.
I would like you guys to confirm something for me. I know it's kinda silly but need a little confirmation.
Is the bolt of the power steering pulley rotates with the pulley or is it stationary?
11-03-2015, 08:57 PM
