I noticed for the first time that when the radiator fans go to their highest speed, and the car is in drive at idle, the voltmeter drops to a reading of 12 from its normal dead center 13. The lights dim a little as well. When I drive off the voltmeter returns to 13.

My battery checks in at 12.77 with the engine off and 14.5+ with the engine on, which I believe means that the alternator is charging. The alternator is only a few months old. I cut everything on, included heated seats, lights, you name it, and the voltage still reads above 14 with engine running.

The car just turned 68K. I have owned since 55K (a little over a year, and I never noticed this voltage dip before.

Thoughts?

 

Yes, it's fine. Alternators produces little/no current at idle.

 

I am starting to believe one of the fans is going bad. It came on again today at a stoplight and began making a mechanical racket like it was coming apart. Will have to have checked by an indy. I'll let everyone know what I find. A new fan assembly in north of $600, based on a cursory check. I know that the voltage never dipped before now, so this is a new issue.