There is a high pitch squeal under my hood. I tried the trick of putting a screw drive on it and listening and it sounds kind of rough but it might be the idle of the engine.

My car was sitting for 4 months but I started it about once a week and drove it up and down my driveway to keep things moving. I insured it a few days ago for spring break.

I never noticed the squealing until a few hours after I had started driving it again. My volts gauge dropped to about 10-11 because I had my rear def on, defrost, cd player, headlights, wipers. I shut off everything but wipers and headlights and it came back up to near 13. This was at a stop light though, while driving it would be above 13 volts.

Right now the volts gauge doesnt dip that far but at when idling it will be right on 13 and when driving I assume 14.4V.

Also a weird thing I noticed.. everytime when the car starts up the gauge will go up to about 13.. dip a slight bit below and then it will rush up to around 14V and stay there until I put the car in gear and turn some accesories on where it will go back to 13. When driving everything seems fine.

Could this be my belt slipping? Also could this be getting slightly better and not worse because of my battery being charged by my alternator when I was most likely weak after sitting. Any pointers would be helpful before I tear off my alternator to get it tested. Thanks.

 

Could be the alternator going. If it's squealing you could have any number of things causing that from a dry bearing to a bad voltage regulator pack. If the car has a serpentine accessory drive system, as good a system as the serpentine system is it places a lot of wear on the alternator's rear bearing., which wears out creating a lot of heat and frying the diodes in the regulator. I've seen this many times on cars with serpentine drives.

 

If thats the case, then I guess a rebuild kit is in order. Should I leave it on the car to do that? Or take it off?

 

Just replace the alternator much simpler and more reliable

 

Brand new? Or refurbished?

 

I'd get a new one I've used remanufactured units only to find they dont operate at the specified current rating for that car. Unless of course you are having it rebuilt by an alternator shop you know. I have had that done, I just don't live close to the guy anymore.

 

Your problem might be the alternator,but first consider the following.
The description of the problem sounds like the pulley belt is slipping. The way you describe the squealing & the fluctuating volt gauge, I had exactly the same thing 2 weeks ago on my 85 Transam. My solution was to get new pulley belts.Make sure your battery also has a good charge in it to keep the 14volts constant. You said you put a screwdrive on the alternator & it sounded rough, that would be the vibration of the engine that your hearing. Good luck !

 

Hmmm... Maybe, If he hasn't replaced the belt recently that is a given, definitely replace it. I am so in tune to my engine that a new belt is about an annual event. They are so cheap and easy to replace I take for granted that some folks do not maintain their car as I do.
As I said in a previous post, the alternator takes a lot of abuse from the serpentine drive, so, it could be anything in the charging system, including a belt.

 

Okay I rebuilt the alternator myself and replaced everything but the front bearing because I couldn't figure out how to get the front casing off (instructions didnt say). The alternator charges fine now, but the squeeling is still there. So I replaced the belt with a brand new one (cheap, $16 canadian) but that didnt fix the squeeling. New belt looks a lot better than the old one though.

I suppose the front bearing caused enough heat to fry the alternator before, don't want that to happen again so does anyone know how to get at it? I'm sure its retarded. :P

 

Your squeal could be something else. I recently rebuilt a 4.3L in my Blazer I had a very irritating squeal that I couldn't track even with a mechanics stethiscope. I ran the engine and just watched the serpentine drive and as the belt passed over each pulley. After about 20 minutes of this I noticed the belt slipping sideways just a tiny bit on the plastic idler pulley. When I rebuilt the aluminum drive mount, I apparently got the idler pulley on backwards, which I was surprised made a big deal, but the pulley had a worn in track and the belt was trying to wear to a new track slipping sideways to the old wear mark thus making the most noisy squeal. Reversed it and problem solved. If you've replaced any accessorry check them for pulley alignment, some old stuff may even be worn out.

 

Sounds like you burned out your alternator with a low battery. If it had been sitting and the battery was low then the pull was too great on the alternator to run the car and charge the battery and the alternator will go out.