# belt /pully (?) noises - help identifying? - '97 Altima



## belacane (Nov 9, 2011)

Hello all,

I have a '97 Altima that has been making a rather interesting noise over the past few weeks, and I'm curious about others' opinions..

I think I can best describe it is a 'rotating, grinding, somewhat bubbly noise'. It's much more audible from inside the cabin than outside, and seems to be coming from the center (maybe closer to the passenger side) of the engine closest to the cabin. 
It's significantly quieter in park and neutral, and louder when in gear.

It doesn't seem to have the traditional squeek or chrip that a bad pully/belt often gives, but definitely sounds like something rotating.

Here is a video with the sound, you may have to turn up your volume, as my phone isn't the best of quality. I am interested in opinions and thoughts.







Thanks in advance!


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## belacane (Nov 9, 2011)

also, when park or neutral, the sound will suddenly start incredibly loudly, and then after about 15 - 30 seconds, disappear altogether.


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## belacane (Nov 9, 2011)

anyone? anyone?


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## Caddytech (Mar 19, 2012)

it's really hard to hear the noise in your video but i will tell you it may be your timing chain guides, there's a technical service bulletin on them. i believe the 2.4L is pretty notorious for this. if the noise is coming from the upper timing chain guides the fix is to simply remove the guides which i just had to do on mine, it takes a couple hours to do or if you take it to a shop i would guess it would cost you somewhere between $200-$500 (just a guess). if its the lower chain guide, you may get pieces of plastic in your oil pan and supposedly some pieces may come out when you change the oil. if its the lower guide the fix is to replace the plastic guide with a metal one and it's a bt more expensive because you have to remove the front cover and water pump and stuff, i don't even know how much that would cost. i heard that if you just let it go that it doesn't really affect it, but i don't know how much i would trust that, i have no evidence really to back this up, just a friend who works on a lot of japanese cars. mine apparently had some type of engine noise reducing additive in it, as the noise appeared immediately after i changed the oil a couple days after i bought it, so maybe that's proof, i don't know....


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## altimanum1 (Jun 19, 2009)

The best thing yo can do is remove the belt after you remove it turn each pulley one by one and try identifying the bad one.


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## belacane (Nov 9, 2011)

Caddytech said:


> it's really hard to hear the noise in your video but i will tell you it may be your timing chain guides, there's a technical service bulletin on them. i believe the 2.4L is pretty notorious for this. if the noise is coming from the upper timing chain guides the fix is to simply remove the guides which i just had to do on mine, it takes a couple hours to do or if you take it to a shop i would guess it would cost you somewhere between $200-$500 (just a guess). if its the lower chain guide, you may get pieces of plastic in your oil pan and supposedly some pieces may come out when you change the oil. if its the lower guide the fix is to replace the plastic guide with a metal one and it's a bt more expensive because you have to remove the front cover and water pump and stuff, i don't even know how much that would cost. i heard that if you just let it go that it doesn't really affect it, but i don't know how much i would trust that, i have no evidence really to back this up, just a friend who works on a lot of japanese cars. mine apparently had some type of engine noise reducing additive in it, as the noise appeared immediately after i changed the oil a couple days after i bought it, so maybe that's proof, i don't know....




Wow... Thank you for this tip! It just so happens that I am taking the timing chain apart to get the head off (head gasket blew... among other things), so I will look into it. 

The belts are all about to go, so those are going to be replaced too, and I'm gonna check out the pulleys too.

Thanks again!


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