# Belt noise: replace idler pulley? - GA16DE



## zzbaomit (Jul 14, 2008)

My car is a 1999 Nissan Sentra, GA16DE engine. 

In 2006 I started to hear some belt noise from A/C-alternator v-belt, which can be silenced by a spray of belt conditioner sold in Wal-mart. But the noise came back sooner and sooner, from monthly to weekly. I then tried to tighten up the idle pulley in 2007. But I made a mistake. I did not loosen the lock nut on the idle pulley before turning the adjusting bolt. After a week or so, the noise is very loud. So I took it to a garage and had the belt changed. It was very quiet. But last month, less than 1yr from changing the belt, I heard noise again. It is getting louder and louder. 

I suspect the idle pulley need to be replaced. The noise is like 'sho----- sho-----sho' at idling. When I give gas, it becomes 'sho-sho-sho'. Also, the back of the belt and pulley surface are shiny, suggesting they are polishing each other. The only pulley touches the back of the belt is the idling pulley. A/C on or not doesn't change the sound. 

Here are my questions: 
I would like to do it myself this time. I have the FSM as pdf from this forum, but it doesn't have much detail on changing idling pulley. Does anyone know how difficult it is? I have done changing engine oil and brake pads. This space there looks very limited. Any special tools? 

I thought I damaged the idling pulley adjusting bolt by not loosening lock nut. But after changing the belt, it was fine. Then why it comes back after less than 1 yr? Maybe this time it is caused by bearing damage? 

Can anyone confirm this is the right replacement for the idler pulley? the part # is W0133-1612180

1999 Nissan Sentra Accessory Belt Idler Pulley - Cooling System - OES Genuine - PartsGeek

Rockauto gives a different one: Gates #36087 without image. My guess is the OES one is better because it has the thread for the adjusting bolt.


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## maroonsentra (Mar 3, 2007)

zzbaomit said:


> My car is a 1999 Nissan Sentra, GA16DE engine.
> 
> In 2006 I started to hear some belt noise from A/C-alternator v-belt, which can be silenced by a spray of belt conditioner sold in Wal-mart. But the noise came back sooner and sooner, from monthly to weekly. I then tried to tighten up the idle pulley in 2007. But I made a mistake. I did not loosen the lock nut on the idle pulley before turning the adjusting bolt. After a week or so, the noise is very loud. So I took it to a garage and had the belt changed. It was very quiet. But last month, less than 1yr from changing the belt, I heard noise again. It is getting louder and louder.
> 
> ...



If you're spraying it and it goes away, you need a new belt. Get a gatorback belt from autozone for $12. It has extra ribs in it to help and prevent the noise. Cheap belts on this car, simply don't work.

Jason


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## zzbaomit (Jul 14, 2008)

I tried to do some diagnosis tonight. 

Spray water to the belt doesn't change the noise. 

Both belts have some worn marks. The grooves are not that deep as new. 

The plan is to change both belts and see what will happen. I will surely try these Gates belts. 

Any one has some insides on how to do this? Any tricks?


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## maroonsentra (Mar 3, 2007)

zzbaomit said:


> I tried to do some diagnosis tonight.
> 
> Spray water to the belt doesn't change the noise.
> 
> ...


Gatorback belts. Autozone will know when you tell them. Pull the passenger side wheel off. then pull small plastic cover that has a few bolts/screws with a couple attaching to the front bumper. Easiest way to losen the main belt, is to losen the idler pulley. To get the water pump and power steering pump belt off you have to get to the tensioner. This is located about near middle, toward the firewall. Losen the nut connected to the power steering and then losen the main bolt. It will take alot of turns, but eventually the belt will get lose. Reverse it to put it back together and make sure you have only 1/4" of tension.

Jason


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## zzbaomit (Jul 14, 2008)

maroonsentra said:


> Gatorback belts. Autozone will know when you tell them. Pull the passenger side wheel off. then pull small plastic cover that has a few bolts/screws with a couple attaching to the front bumper. Easiest way to losen the main belt, is to losen the idler pulley. To get the water pump and power steering pump belt off you have to get to the tensioner. This is located about near middle, toward the firewall. Losen the nut connected to the power steering and then losen the main bolt. It will take alot of turns, but eventually the belt will get lose. Reverse it to put it back together and make sure you have only 1/4" of tension.
> 
> Jason


Thank you very much, Jason!

Your post remind me that there are a few screws missing on the plastic panels in the wheel well. The panel has a big hole, as it touched the wheel. the garage has done a bad job . This time I will do it myself and use good parts! Hope it will last longer. 

I checked the FSM, the lock nut for the PS pulley has a torque of 55.6-73.8 in-lb. But it does not give torque for the 14mm idler pulley lock nut. any one know it?


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## maroonsentra (Mar 3, 2007)

zzbaomit said:


> Thank you very much, Jason!
> 
> Your post remind me that there are a few screws missing on the plastic panels in the wheel well. The panel has a big hole, as it touched the wheel. the garage has done a bad job . This time I will do it myself and use good parts! Hope it will last longer.
> 
> I checked the FSM, the lock nut for the PS pulley has a torque of 55.6-73.8 in-lb. But it does not give torque for the 14mm idler pulley lock nut. any one know it?


I have taken it off several times and never used torque specs. Just make it tight. You'll be fine.


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## zzbaomit (Jul 14, 2008)

*found out why --> replace water pump?*

Hi, just keep your guys updated about my Sentra 99 GA16DE belt noise. 

I purchased the gatorback belt and replaced the belt, yesterday and today. get some exp. like to share but also find new problem. 

My two cents: 
the belt from P/S, water pump is difficult to get off. after loosen both lock nut and adjustment nut, you have to pull the belt or P/S pump really hard to move it towards engine, so that the belt can be released. I used a rope to pull the lock nut. 
every thing is much easier if you remove two plastic panels: one is underneath the engine, the other is on the side of wheel well. then every thing is exposed. 
I also cleaned all the grooves in the pulleys. a lot of rubber debris. I have to use a steel wire brush and a knife. 

What I found: 
the belt for P/S and W/P is in bad condition. a lot of rubber comes off. 
all the pulleys are ok, no much free play, no resistance, except the one on water pump. When I rotate it, there is no resistance but a "zzzz" sound like a mouse. 
After install all the belt, the noise is still there. then I remove one belt at a time and test. found out it is the P/S W/P belt gives noise. with this belt on, there is noise, without it, no noise. 

My question: 
Do I need to replace water pump? How long will it last if not changing it? The noise is not too bad and my daily trip is less than 5 miles one way. I prefer to do it in the next summer if it can last that long. 

I just flushed the cooling system in the past July when it is 9 years old and 67K on mileage. Maybe the flush came too late.


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## maroonsentra (Mar 3, 2007)

zzbaomit said:


> Hi, just keep your guys updated about my Sentra 99 GA16DE belt noise.
> 
> I purchased the gatorback belt and replaced the belt, yesterday and today. get some exp. like to share but also find new problem.
> 
> ...


Sounds like the pump could be bad. Has it been replaced before? Make sure you're using 50/50 and not all water and not all coolant. The coolant also lubes internal parts to prevent them from rusting or seizing. The water pump replacement isn't too bad. I believe there is a walk through on this site if you search. You shouldn't hear any noises coming from it. I'd get a new power steering belt while you're at it. Make sure when you put them back together you only have about 1/4 tension (or able to move the belt). If not, it's not tight enough. Good Luck!

Jason


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