Alternator or not?

[nohitter64]

This evening I got the little battery dash light indicating an issue with the charging system. It cleared after I started the car and then came back on after I drove a short while. Got home and checked the voltage: engine off I have 12.48 volts across the battery. Engine running I have 12.44. All connections appear to be solid. I noticed a "whine" when the engine runs; that started when I had the AC compressor replaced in May so I thought it had to do with that. It increases when I depress the gas pedal.

The Liberty has 149k miles (107k are mine) so I am thinking I am due. If it is an alternator, any recommendations?...easiest for me is Duralast from Azone as they are a block away. The 160 amp version is about $140.

Thanks in advance for your comments.

Ryan

 

[HoosierJeeper]

I read bad reviews of all the aftermarket ones, I got a junkyard one with 60k miles for $60. That was like 20k ago and it's just fine.

 

[JasonJ]

I read bad reviews of all the aftermarket ones, I got a junkyard one with 60k miles for $60. That was like 20k ago and it's just fine.

Both options are perfectly fine... if you get a re-manufactured unit form a parts store, insist that they bench test it before it leaves the building (if they don't do that already).

When I worked there, I wouldn't even hand the alternator or starter over to the customer and finish the sale until I had bench tested the unit to verify it worked fine. I did occasionally find a bad one.

 

[nohitter64]

I tested the voltage this morning and the numbers were fine. And the light did not come on during my 15 mile commute. So now I am wondering if it is the belt. Would the alternator "whine" with loose belt? I heard the noise yesterday and today it went away within a mile or 2. Wondering if I should start by replacing the belt but I feel it is relatively new.

Sent from my SM-G950U using Tapatalk

 

[uss2defiant]

maybe bad auto tensioner?

 

[JasonJ]

I tested the voltage this morning and the numbers were fine. And the light did not come on during my 15 mile commute. So now I am wondering if it is the belt. Would the alternator "whine" with loose belt? I heard the noise yesterday and today it went away within a mile or 2. Wondering if I should start by replacing the belt but I feel it is relatively new.

Sent from my SM-G950U using Tapatalk

You'd be more likely to hear the belt squeal as opposed to the alt whining. Tensioners and idlers and the alternator "whine" when the bearings have become worn and dry.

 

[LibertyTC]

With a new belt & tensioner while pressing inwards, it should be tight and no wobbles while running.
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How old is your battery , what model, and what is the voltage reading after sitting all night before starting, with interior lights off/no drain...??
My AM Voltage Reading..
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While charging at idle my good alternator shows...
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OBD2 reader shows a bit higher charging voltage..
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Even with a load on driving (lights on, fan on high, stereo) voltage should remain close to shown.
You may loose some amps/volts when ALT is HOT. However charging voltage should not be below aprox 13.7 unless severe load or the Alt is bad.

 

[ltd02]

There is a built in belt wear/stretch indicator on the tensioner if you have the OE tensioner. My replacement Gates does not have it.

 

[renegade 04]

Your alternator is most likely bad. I would have it rebuilt by a local alternator rebuilder AKA not your auto parts store.