I've got a new, high-pitched squeel right at starting...

[snowman74]

All,

Finally got that new 3G alternator installed...which was really no sweat. After starting, the belt (I think) is making a high-pitch squealing sound...similar to that like if your belt is loose. The sound goes away after 3-5 seconds or so. I am using the pulley that came with the alternator...which looks to be about the same size as the old one, not sure. I've got a new overdrive pulley that I want to install...but figured I'd better figure out what's going on first. If somebody has had this problem, please let me know what the remedy is. Thanks.

Snowman74 >-

 

[firelt90bronco]

How new is the belt itself? Also make sure all of the pullies are free spinning and that there is no bearing noise.

 

[Seabronc]

V-belt or serpentine?

3G Used, re-manufactured, new?

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[snowman74]

The belt is serpentine. It's probably about a year old...I don't let them get very old. The alternator is brand new. Since this post, I've started it a dozen times...each time the squealing sound shortens in duration. Now it's only a quick squeal sound right as the engine starts up, and then it goes away.

On the same subject, I'm watching my voltage... In the winter (prior to installing new 3G) I had noticed when I turned on the heat or vent, the voltage dropped from right at 15, down to 12 or so (needle pointing straight down on stock gauge). I thought this would be remedied by replacing the alternator...but it's not. Still does it. Suppose I've got some kind of wiring problem with my hvac system? Where should I start to troubleshoot this problem?

Thanks Jim and Fred...

Snowman74 >-

 

[snowman74]

The belt is serpentine. It's probably about a year old...I don't let them get very old. The alternator is brand new. Since this post, I've started it a dozen times...each time the squealing sound shortens in duration. Now it's only a quick squeal sound right as the engine starts up, and then it goes away.

On the same subject, I'm watching my voltage... In the winter (prior to installing new 3G) I had noticed when I turned on the heat or vent, the voltage dropped from right at 15, down to 12 or so (needle pointing straight down on stock gauge). I thought this would be remedied by replacing the alternator...but it's not. Still does it. Suppose I've got some kind of wiring problem with my hvac system? Where should I start to troubleshoot this problem?

Thanks Jim and Fred...

Snowman74 >-

 

[Seabronc]

I see a similar voltage drop when my electric fan and lights are running, with a after market meter, but It is because of where the meter is hooked up. If you really want to know what the voltage is from the alternator, make the test point at the start solenoid (battery side). Also, most Ford 3G installations have the voltage sense connection right at the alternator output lug (yellow wire that wraps from the 3 wire plug to the output lug). On suggestion of Ron Francis wiring, I moved this point to sample the voltage to the battery side of the start solenoid. That really has an effect on voltage regulation, even though it is only a couple of feet further away from the alternator. He says that your sense point should be where the major voltage distribution point is. I'm making some rearrangements to my electrical system so when I do that my meter test point will be there also.

That voltage drop seems to be excessive, but it all depends on where the meter is hooked up. Some points will show a larger drop than others due to the load on that particular circuit. I would look at it with a digital volt meter and check the voltage at the battery. If it shows a large drop there, then move the alternator sense point and check it. I wouldn't get to concerned about a 2 volt drop at any other point.

As far as the squeal, maybe the belt is a tad too long with the alternator pulley you have. You could try using a belt that is about 1 inch shorter. Have you had someone else start it while you try to locate the source of the squeal?

Good luck,

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