# Alternator not charging battery



## newb15 (Apr 4, 2014)

Alternator (removed and tested at AAP) is new and tested good. Same goes for the battery. So both tested good. (I replaced the old alternator assuming that this was the problem, but that was not it and I got a new battery because older one went flat after many jump starts)
I tested the charge level with the car off, battery was at 12.63V and went down to 12.25V with the car running, so the alternator is not doing its job, but it is new and was tested and advance auto parts(AAP) guy told me that the alternator and battery are both good. I checked the fuses for the alternator and battery and they were also good. 
Any ideas?

-Its a 2000 Nissan Sentra 1.8 if that helps.


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## otto888man (Dec 30, 2013)

Have you checked the Maxi fuses near the battery?


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## newb15 (Apr 4, 2014)

I checked the fuses, they are fine. Im thinking that its the alternator belt now, because the pulley that connects to the tension bolt is wobbling and the nut that connects the pulley to the nut is not even the original one because it fell out of the car and the guy I got to replace the alternator got a nut that does not fully tighten to the tension bolt. Anyone know what size bolt I I need? The alternator pulley wobbles and the belt is slowly spinning(and even looks like its about to slip out from under the pulley itself), which I believe is causing the issue.


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## rogoman (Dec 16, 2004)

Just to make you aware, all the nuts and bolts on the car are metric, not SAE. Your "master mechanic?" probably installed an SAE nut which is why it's not tightening properly. The bolt is most likely stripped. To do it properly, remove the tension bolt and make sure the threads are in good condition, not cross-threaded; if cross-threaded, it can be restored with a thread-chaser. Take the bolt with you to a hardware store and get a matching metric nut.


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## newb15 (Apr 4, 2014)

Anyone know where I can get the nut that connects the idler pulley to the square head tensioner bolt? I went to auto parts store and home depot and neither have the nut. The thread on the bolt is still good.


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## worthirt (May 21, 2013)

Take a look at Lowes, I usually end up going there. They seem to have a better selection of Metric hardware from what I have found.


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## rogoman (Dec 16, 2004)

newb15 said:


> Anyone know where I can get the nut that connects the idler pulley to the square head tensioner bolt? I went to auto parts store and home depot and neither have the nut. The thread on the bolt is still good.


You can always check with junk yards.


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## newb15 (Apr 4, 2014)

Yeah I was thinking Lowes too, but I'm probably going to the junkyard because I'm better off getting the original part.


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## worthirt (May 21, 2013)

Forgot about the "yard", it would prob be best to go there actually.


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## newb15 (Apr 4, 2014)

Got the piece I needed from ace hardware...but now the idler pulley is rubbing on the alternator, causing the belt to move slow and still wobbles. Is there a part that separates the idler pulley from the alternator that might have fallen when the original nut and idler pulley fell?


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## rogoman (Dec 16, 2004)

There may have been a spacer that fits behind the pulley. You'll have to look at another Sentra to determine that.


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