My 2007 Altima has started making a squealing noise located somewhere near the front of the engine (belt area) when the car is turned off. The squeal lasts maybe five seconds. I'm guessing it may be a bad bearing in perhaps the water pump? Has anyone else had this type of experience?

Dirt or more likely greasse on the fan belt ?

Five seconds is a heck of a long time, roughly 50 revolutions at idle speed. If it's taking that long for your engine to stop spinning, then it has to be "running on" from preignition. That can cause belt noises all by itself from the staccato accelerations of the crank pulley.

I'll check for dirt on the belt, but I think the engine is pretty clean. And yes, I was shocked how long the squeal lasted after the belt stopped turning.

Btw, I don't know if this is important, but I had cleaned my throttle body about a year ago. The car immediately started running rougher. I took the car to a mechanic and he said that sometimes it can be reset with Nissans, but many times the throttle body may need to be replaced. Anyhow the reset worked for a while. Recently the car has been idling at 1700 - way too high. I wonder if this is somehow related?

Video of squealing noise:
https://youtu.be/GNA4GcdqhNE

That isn't the belt, something is still spinning without the belt after shutdown. It could be the water pump impeller off the splines, but that will usually overheat you at highway speed. Could be any shaft that can still spin if it comes loose from its pulley. alternator and P/S are also candidates, but the alternator is most likely since you didn't mention high steering effort. The alternator has an overrunning sprag clutch built into the pulley that might still be able to push the alternator forward without having any resistance in the other direction, letting the rotor keep spinning after the belt stops and the field coils shut down.

Thanks Vstar, I will try to get a better look today. So you don't think that the high idle from the throttle body issue could be connected in any way?


Car Noise Video:
https://youtu.be/GNA4GcdqhNE

No, from the video it looks like the engine shut down normally without any run-on. That squeal doesn't sound belt-ish anyway, it sounds much more bearing-ish. That would jive with the alternator as well.

Thank you sir.

You're most welcome! Post back when you get to the bottom of it, others will want to know.

I have an appointment for next Wednesday. I will post the results. I suspect bearing in either alternator or possibly another pulley.

Car noise video:
https://youtu.be/GNA4GcdqhNE

The results to the squeal are in. The problem was the alternator. Bad clutch.

Also, the shop did a "relearn" on the idle. I'm hoping that works so that I don't need to replace the throttle body. Just don't try to clean the throttle body on these vehicles. It will mess up the idle.

chimp wrote: ↑

Thu Nov 11, 2021 5:32 am

The results to the squeal are in. The problem was the alternator. Bad clutch.

Also, the shop did a "relearn" on the idle. I'm hoping that works so that I don't need to replace the throttle body. Just don't try to clean the throttle body on these vehicles. It will mess up the idle.

Glad you got it straightened out! Cleaning TB's isn't a bad thing, folks just don't do it right. To do it in situ without removing it, forcing the plate open is a bad idea. Brick the pedal and let the throttle motor hold it open. Then make certain to get the back edge and back side, those are the critical points for carbon buildup. The right tool is a stiff toothbrush. Once you're done, an IAVL (Idle Air Volume Learn) is absolutely necessary. Half the "after cleaning" problems people have are from not knowing about IAVL or thinking they can skip it. Do the job right and there are rarely any issues.

The shop did a relearn again and the idle is working well again. Cleaning the throttle body is definitely more tricky on my 2007 altima than other vehicles.