New Alternator Gets Hot

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64nailhead

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Dec 1, 2014
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Impossible to tell what the issue is presently. Bad grounds are just that and will cause issue everywhere all the time of the are crappy. A quick test is to run a couple of extra grounds, 10 gauge cable minimum, from the the engine and body to the battery. Charge wire needs to be good as well - make a new temporary one or use a jumper cable off the charge post to the battery. If the alternator is still getting hot, then it's a dud or you have a helacious short somewhere drawing more amps than the alternator can output.

The easy way out is to get a new alternator and try it, if they will give a new one for free. If not free, then easy way just became more expensive if you fry the second one because of a wiring problem.
 

303'505rollin

G-Body Guru
Sep 4, 2020
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I just bought a 94 amp duralast as my old alt was slowly lighting the light, any way its agood alt but its case was clocked wrong and to open it and reset it. Something could be wrong internally take it back and try again
 

MrSony

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Nov 15, 2014
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That alternator was the only one they had in stock at that moment that would fit, according to them. They wouldn't let me open every box. The ground.is hooked to the alternator bracket bottom bolt. It's aluminum. That good enough? Would putting it on the head make the cable too hot? My old alt I still have I might take it to a rebuilder the brush holder is broken and the springs went somewhere. It worked fine when it worked but it would no longer charge with headlights on and at peak was only putting out 12.7ish volts at max plus as said it rattled so loud i thought a rod let loose again..
 
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CopperNick

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Would depend on exactly where that ground lead is attached. If to that lower front plate through which the long bottom bolt goes through then the ground would go through the engine via the two bolts that attach that mount to the water pump. If attached directly to the case of the unit, would consider shifting the ground lead off that attachment point and moving it to an empty threaded hole on the head or to a stud or bolt holding the exhaust manifold or header on. Would also likely make a whole new ground lead and go big with the wire gauge, say 6 or 4. Take this ground right to the frame and make sure the attaching point is CLEAN, then run a second wire from that point to the ground terminal on the battery. This assures that the engine has a good secure ground and that ground continuity between the engine, frame, and battery is clean and uncompromised.



Nick
 
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g0thiac

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Sep 6, 2020
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That alternator was the only one they had in stock at that moment that would fit, according to them. They wouldn't let me open every box. The ground.is hooked to the alternator bracket bottom bolt. It's aluminum. That good enough? Would putting it on the head make the cable too hot? My old alt I still have I might take it to a rebuilder the brush holder is broken and the springs went somewhere. It worked fine when it worked but it would no longer charge with headlights on and at peak was only putting out 12.7ish volts at max plus as said it rattled so loud i thought a rod let loose again..
Mine used to be on the bottom too, I ran mine from the battery to the block directly, and then ran another ground from the old bottom bolt to the body.

There shouldn’t be much confusion here, either the alternator is defective (which most part stores can test for) or you have heat from either too much amperage being pulled or a short circuit.

If the cables are original? Replace them. Takes less than an hour if that even without a lift.
 
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MrSony

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Welp that alternator took a sh*t. I think it got hot and the voltage regulator died. Needle was goin nuts. Never done that before.
 
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MrSony

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Went back and asked them to test it.
"Yep that's waaaay over charging. You... should shut that off."
New alt coming tom. Pro tip: don't get the one that looks like Ace Ventura delivered it.
 
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CopperNick

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Meaning that if the box and contents look like someone was using them as a soccer ball, y'oughts take a pass on it???



Nick
 
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MrSony

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Got a free replacement. had them test it on the car. all is good.
 
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