Mysterious Squeaky Belt Issue

2005 Infiniti G35 Base 6 Cyl
Okay takes a breather, now I am hoping someone can help me with my issue here. When the car is cold and I start it up, there is a schreeching noise only a banshee could mimick. There are 2 belts. One belt (could be both knowing my luck) is/are making this loud noise from hell. It goes on for about 3 or 4 minutes or maybe 2 on a good day. Just the other day I decided to turn my headlights off to park my car close to my exit door at work to give it a warm up. When I turned the lights off (they are usually set to auto) the screeching stopped. I’ve learned now this will kill the noise almost all of it except for the first start of the car. Also having the heat on makes it worse too so I have to remember to take heat off when I park the car after arriving at my destination. What could my issue be? Thanks for your time.

Sounds like the culprit is the belt driving the alternator. When you decrease the electrical load, there is less load on the alternator and therefore the belt. However, if replacing or properly tensioning the belt doesn’t fix it, it could be the bearings in the alternator.


However, I feel compelled to add the following question for the OP:
Do you really think that those 13 year old drive belts will last forever?

Rubber compounds harden over the years as a result of heat exposure, and your drive belts have been subjected to a lot of engine-related heat over that 13 year period.
That intense heat exposure does take its toll.
It’s not really a mystery!

I replaced one belt about 6 months ago because it felt a little worn compared the other once. (Can’t remember if it was the belt that had the alternator, I remember there is a wide belt with several components it was turning, the other was thinner, and not turning as much) I changed the wider one. And it was squeaking then, same deal, and the noise went away! Until about a month and a half ago!

I thought with the year of the car viewers would automatically assume belts are not original given it’s from 2005. I’m not expert here so that’s why I am coming to you guys for advice, I just thought that would automatically assumed so I am sorry. I bought the car about a year and a half ago. It was not squeaking at first. Then about 8 months ago it started squeaking bad like it is now - I changed one of the belts, and the noise went away so I thought, problem fixed - about a month and a half ago the noise came back!

That would be the serpentine belt. Has the tensioner been replaced? If it doesn’t move smoothly or the spring has weakened, you’ll get squealing.

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Both belts should be turning. Replace the second belt and see if it still screeches. If it does, then you probably need to replace a pulley.

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I have not changed the tensionor and I have had the car for about a year and a half. So I think I may change it the next warm day we have here. The only thing that boggles me is that when I changed the serpentine belt - the noise went away until recently

The brand new belt plus the finagling with the tensioner to get it on bought you temporary quiet.

Okay, how will I know what pulley?

Okay I guess that makes sense to me. So you mentioned a spring? Can I replace that at the same time?

Okay, looking at a YouTube video of belt replacement, your car does NOT have a spring-loaded tensioner. The belt is tightened by turning a bolt from underneath.

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Spin it. If it makes any noise or sticks while you spin it, replace it.

Yes a tensioner is a good possibility, but a length of heater hose used to locate the source of the sound, or a stethoscope can help narrow down the problem so you can find the bad part before throwing parts at it.

You are the tensioner, you must set the belt tension when replacing the belt. Tighten the alternator belt, it is not tight enough.