1995 BMW 740 low voltage

1995 BMW 740
12,000 MILES • V8 • 2WD • AUTOMATIC
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BRIANPK
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  • 2 POSTS
purchased new allternator, volt reg. is fine...however, when car warms up its losing aprox 3volts. replaced belts to no avail. running at 12.2 volts?? Car needs 14.5 I'm told. Is there an external regulator?
Nov 26, 2008 at 12:31 PM
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DOCHAGERTY
  • ✓ASE Certified Mechanic
  • 9,606 POSTS
  • ASE Certified Mechanic
Was it a new or rebuilt alternator? If you are having issues with voltage regulation, the alternator is the cause and they are internally regulated. Did you get a warranty?
Nov 26, 2008 at 2:02 PM
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BRIANPK
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Hey "doctor", as my question stated, it is a brand new alternator, voltage regulator was checked by certified mech., Output from battery is fine for 2 minutes then it drops a few volts, radio stops working, car seems to run ok. So what do you think? Bad battery (I know the battery also serves as a voltage stabilizer) or do you think I've got a dead short somewhere?
Nov 27, 2008 at 3:59 PM
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DOCHAGERTY
  • ✓ASE Certified Mechanic
  • 9,606 POSTS
  • ASE Certified Mechanic
It could be the battery, what did the mechanic that installed the alternator have to say? It must have seemed a bit unusual to a certified mechanic to install a new alternator and have this happen.
Nov 28, 2008 at 12:05 AM
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