The voltage is surging very badly when the car is first started and for the first few minutes you drive it. Does not affect engine, except you hear the cooling fan and AC fans surging up and down---but engine RPM is not affected noticeably. After a few minutes of driving, the problem goes away. I guess this would have to be a bad voltage regulator? I don't know whether the regulator in this car is internal to the alternator or external. If it is internal, do I need to get a rebuilt alternator, or is it something that a weekend mechanic can replace himself?
Voltage surging on 89 740 GL!
Jun 10, 2004
1 Replies
The regulator is internal, but mounted on the outside of the alternator. If your alternator is mounted high on the left side of the engine you can swap it out with the alternator still in place. You should really check the voltage at the battery while the problem is occurring to make sure it's not a problem with the wiring.
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