08 Box Base Alternator

[vza]

Did an Alternator test by attaching a multimeter to my terminals with engine running. It read about 12 volts then proceeded to go lower, at some point down to 10.5.

I assume the alternator is not charging the battery or there is a connection problem, possibly the ground. The batt is not holding a charge either. Thoughts? V

[Loren]

Or a flat battery.

I always suspect the battery first unless I have load tested it outside of the car.

[vza]

Ok.... so it could still be the battery even though I'm only getting 10 or so volts with the engine running across the terminals? V

[JFP in PA]

9 hours ago, vza said:

Ok.... so it could still be the battery even though I'm only getting 10 or so volts with the engine running across the terminals? V

 

Yes. A bad battery can act like a black hole for alternator output.  As Loren noted, get the battery load tested, if it is bad, replace it. If the alternator still has low output, it is probably the voltage regulator which can be swapped out as well.

[vza]

OK Thanks gents...I'm counting on you guys getting me thru this project. Lots more questions coming your way. V

[vza]

Ok...Battery tested good ...but ....it wasn't the correct battery for the car so I dropped in a new one. Measured voltage across terminals w/ engine running and got around 10.5 volts. I assume its the alternator or voltage regulator. Will check connections and ground. Any thoughts. Thanks V

[JFP in PA]

You should be seeing around 14.5 V with the engine running.  Either the voltage regulator or the alternator itself is bad,

[vza]

Should I take a chance and replace the regulator first? V

[JFP in PA]

That’s a call only you can make; in my world, voltage regulators are a lot cheaper than a new alternator.

[vza]

Managed to get my alternator out and I think I need more than Voltage Regulator. I noticed 2 wires burned up(pic of 1 of them) I guess these are wires to the Diodes. I did smell some electrical burning when test driving .....maybe the alt?  Would it be okay to use an alternate reman alternator ie.AC Delco. They are less expensive than the Bosch. Thanks V  

[JFP in PA]

I never used anything other than the Bosch on customer cars, so I cannot comment on the Delco units.

[Silver_TT]

My opinion but just buy a new OE alternator and be done with it....

[vza]

Ok so I got my reman Bosch alternator. The pulleys look the same on new as old but act differently. They both have a plastic covers which I think means they are a free wheel lock pulley. The old pulley turns the stator one way (not forward and backwards)if I stop the pulley the stator continues to turn(guess thats when its free.) The new pulley seems to turn the stator both ways ...forward and back and does NOT allow the stator to continue to rotate when stopped with your hand.(not free). I assume the free wheel mechanism engages at a higher rpm and the pulley is bad on my old one as well.V

[Silver_TT]

yes there are different versions of the alternator -- freewheel/clutching and not.  Did you check the part you bought against your VIN to ensure you got the right versison?

[JFP in PA]

Manual transmission cars used declutching alternator pulleys, while the Tip cars did not.

[vza]

Yes, Is there a way to tell if its a declutching pulley on my new one? V

[JFP in PA]

How declutching alternator pulleys work

[vza]

Thanks Jeff....I have a bonafied declutching pulley. 

[Loren]

56 minutes ago, vza said:

Thanks Jeff....I have a bonafied declutching pulley. 

 

It os actually John (not Jeff).

[JFP in PA]

15 minutes ago, Loren said:

 

It os actually John (not Jeff).

 

Call me anything but late for dinner................😉

[vza]

LOL...