So when I do a cold start, I get few seconds of what sounds like belt squeal. Only happens on cold starts though.

On a possibly related issue, the past few days I have been riding with the windows down. Seems like when I'm off the gas and at about 2000-2400 rpms, there is a very faint squeal. It is possibly it's there at higher RPMs but is drowned out by engine and exhaust noise. No squealing at idle though, except at cold startup mentioned above.

Both belts seem to be tight with only a few mms of play in them. The wider belt has less than 10k on it, but when I think about it, the startup squealing may have started shortly after it was replaced. The smaller belt is in decent shape, maybe just a little bit fraying on the edges. Alternator gauge shows about 14V, so I don't think the alternator is going out.

What does this sound like and what do I need to check?

 

Does depressing the clutch pedal affect the "squeal?"

 

Might be one of the belts, or it might be a bearing in the tensioner or idler pulley. Not sure if your car has one or both, because my HR is different (one serpentine belt). If you pull off the belts, and there's no noise, spin the pulleys and you'll be able to feel the scratchiness of a bad bearing. Could be a vacuum leak, too, especially if it gets better when you jump on the throttle.

 

Only when cold - I'm betting belt...have the tension checked

 

So I just went out to start the car, figures, one of the few times it barely squealed on startup. Will try it again in the morning to see how the clutch affects it. In the past I've tried giving it a little gas, but that doesn't seem to make a difference. I have noticed that it doesn't matter if the AC is on or off on startup.

if the belt is a little loose, could that be causing the faint squeal when coasting at low ish RPMs?

 

It could. Also, once a belt starts slipping and its riction surface becomes polished and slick, it's just easier and better to change the belt. Overtightening puts extra stress on the belt and all the associated bearings/pulleys.

Also, avoid cheap imported belts. Buy a good quality belt, either from Nissan or a Gates, for example. I've used cheap <$10 belts on a few of my cars, and they always cause problems after a short while. I like the NAPA premium belts, which are US-made Gates belts.

 

So the car finally did the startup squeal again. Pressing and/or releasing the clutch has no effect on startup squeal, neither does giving it gas. I'll try tightening the belt up later this week.

On the "squeal" I was hearing at low RPM while driving, I don't think it sounds like a belt squeal. Still not sure what it is, but it sounds closer to a brake squeak than it does belt. I don't think it's the brakes as I never hear the sound while braking, only while coasting or at low RPM driving. Does sound like it's coming from somewhere in the front end though.

 

Checked your brakes lately? Typical behavior of worn pads.... squeal that stops on brake pedal application.

S'far as the belt squeal, use the old Auto Shop 101 test. Put a little WD-40 (don't judge me, I know it's not great for the belts) on the pulleys before starting, fire it up and wait a second. If it stops after a second or three, your belts or pulleys need attention.

Don't they teach that old trick in "Car Forum 101"? Oh, no, too old school. Laff....

 

The squeal only last about 5 seconds without WD40.

 

So try it WITH WD40 and see what happens. If the first time isn't enough, shut it off and try it again.

 

Hate to necro a thread, but I'm getting a cold start squeal too and it looks like you might have some insight since pressing the clutch pedal makes my squeal go away. When I release it, it starts squealing again. What might this mean?

 

What you describe might be the throw-out bearing. If that is the problem, you need a clutch assembly replacement (which is expen$ive).