1995 BMW 740 low voltage

BRIANPK

MEMBER
1995 BMW 740
V8
2WD
AUTOMATIC
12,000 MILES

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?

Wednesday, November 26th, 2008 AT 12:31 PM

3 Replies

DOCHAGERTY

MECHANIC
9,601 POSTS

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?

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Wednesday, November 26th, 2008 AT 2:02 PM

BRIANPK

MEMBER
2 POSTS

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?

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Thursday, November 27th, 2008 AT 3:59 PM

DOCHAGERTY

MECHANIC
9,601 POSTS

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.

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Friday, November 28th, 2008 AT 12:05 AM