Did I get a bad alternator?

[Mark72]

Last week my mechanic installed a brand new alternator on my 2000 Dodge Caravan. When I picked it up from the shop it was fine, made no noise, everything sounded great. The van has been sitting for the past two days and when I started it up a few minutes ago the alternator was squeaking. I know it’s not the belt. The sound is coming right from the wheel that the belt goes over. Does this mean I have a defective alternator? Or can they make those sounds and be functioning properly? The sound is that of a bad barring in the wheel.

 

[LargeCarManX2]

I brought my alternator down to have the bearings replaced because they were squeaking. Came home, put on that alternator and the same squeak existed. Went for a test drive, suddenly the temp guage went to hot, then back to normal. Drove in the driveway and lifted the hood. The noise was gone....and has not returned since?

My therory is a tine or blade on the water pump was scraping the housing-broke off and is in the system somewhere. I have put over 500 miles on since without any issues. Good luck with your squeak.....Yikes

 

[Donald]

How about a tensioner is making the noise? Assuming you have a serpentine belt.

 

[45ACP]

Its more fun when you get a bad Water Pump and you hear bearing squeal after you put it all back together.

 

[NHGUY]

Brand new or rebuilt? Was the belt replaced at the same time?

 

[wrcsixeight]

When alternators go out, batteries get deeply discharged. If the battery is not brought back to full charge by a source other than the alternator, then the newly installed alternator will be asked by the battery to deliver every single amp the alternator can produce at any given rpm. If it is a newly reman'd alternator, the brushes have not broken in to the armature yet, and might glaze over. Mine came with a little CYA sticker statement saying the battery must be at 12.6+ volts before the engine is started for the first time after the alternator is replaced.

This can cause the belt to squeal when the battery is asking for 75+ amps. Usually RPM makes the squeal louder.

It takes many many hours of driving before an alternator can return a battery to full charge. Short trips around town with multiple stops will never do it.

Try putting a 10 amp charger on the battery overnight and see if it changes the noise the next day. This costs next to nothing and is a good place to start.

 

[Chris142]

Originally Posted By: NHGUY
Was the belt replaced at the same time?
Bingo. Probly running a used belt on a new pully.

 

[Donald]

Originally Posted By: wrcsixeight
When alternators go out, batteries get deeply discharged. If the battery is not brought back to full charge by a source other than the alternator, then the newly installed alternator will be asked by the battery to deliver every single amp the alternator can produce at any given rpm. If it is a newly reman'd alternator, the brushes have not broken in to the armature yet, and might glaze over. Mine came with a little CYA sticker statement saying the battery must be at 12.6+ volts before the engine is started for the first time after the alternator is replaced.

This can cause the belt to squeal when the battery is asking for 75+ amps. Usually RPM makes the squeal louder.

It takes many many hours of driving before an alternator can return a battery to full charge. Short trips around town with multiple stops will never do it.

Try putting a 10 amp charger on the battery overnight and see if it changes the noise the next day. This costs next to nothing and is a good place to start.


I got my Suburban back from a shop once when it would not turn over. I asked what was up and they said every time they worked on it they would need to jump it. One might think a brain cell would have energized in their head and they would have looked into it. But no. The Suburban ran like cr*p all the way home. I put an AC charger on it at home and noticed it was not charging up like I expected. When it got dark I found a dome light had been left on. It was just holding the battery at dead all the time it was in the shop.

The alternator is designed to put back the charge of starting and produce enough power to run your lights, fans and radio, etc. Not charge up a dead battery. They do make high output alternators but they are mostly on boats or RVs and in many cases require dual belts.

 

[moklock]

New belt might not hurt if it has some age.

I have also had an alt. make a little extra noise and then "wear in" or something and be fine.

I also once had a new alternator from NAPA need two replacements due to rear bearings slinging out their grease packing right off the bat, so it is possible to have a new/reman alt. have problems just from being built with low quality parts.

 

[Garak]

Originally Posted By: wrcsixeight
When alternators go out, batteries get deeply discharged. If the battery is not brought back to full charge by a source other than the alternator, then the newly installed alternator will be asked by the battery to deliver every single amp the alternator can produce at any given rpm. If it is a newly reman'd alternator, the brushes have not broken in to the armature yet, and might glaze over.


That's exactly the way it should be done. Heck, it should be done that way every time a battery winds up deeply discharged, whether or not the alternator is new, a rebuild, or still working fine. Alternators are meant to keep charge up, not fix dead batteries.

 

[SteveSRT8]

Gone are the days of 60 and 70 amp alternators.

Now figure 180 and up, with 210 or more not that uncommon.

The days of an alternator being taxed by a battery are gone as well.

 

[Garak]

Originally Posted By: SteveSRT8
The days of an alternator being taxed by a battery are gone as well.


If I nursed my car into the garage with a dead alternator and a low battery, even with today's alternators, I'd still be giving it a good charge before subjecting a brand new alternator to a dead battery.

 

[1 SX]

You know... I jumped a car that was sitting for some time, it had a stone cold dead battery... took a little time to get the other car started, but it did.. a few days later, my alt gave out....

 

[Garak]

Originally Posted By: SL2
You know... I jumped a car that was sitting for some time, it had a stone cold dead battery... took a little time to get the other car started, but it did.. a few days later, my alt gave out....


That's one of the reasons I forbade the taxi drivers from giving boosts. The other reason was because of electronics like the meters and radios that tended to go funky after giving a boost.

 

[mechtech2]

Charge the battery .
Give it a week of driving. If the noise is still there, bring it back.