Guys,
I noticed the last couple of mornings that my voltmeter gauge is swinging wildly between the 8 and 14. After five minutes of driving, it seems to stabilize at normal level and stays steady. I am concerned about the health of my battery/alternator. What might be causing this swing?


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1993 Aerostar 4.0L, 187K miles

 

I was getting a swing in my 90 Aero, not as bad as yours, but enough to take notice, Battery/alternator checked out good. The neg battery cable insulation was peeling off and was told by machanic that knows more about newer cars than I that this would be a problem, so I replaced it and the gauge went back to normal.

 

does engine start ok? clean and check battery connections
may be failing brushes-split rings in alternator

 

I'd say the alternator brushes are probably worn down. Check and replace the brushes (only a few dollars) rather than wait until the graphite is all gone and the steel springs eat into the ring. Then it would be expensive.

 

There are parts stores that will do a free check of your starting / charging system in hopes that you will buy their parts. Make a couple calls after cleaning your battery posts fails to correct the problem.

 

Well, the problem turned out to be the alternator. I took the van to AutoZone yesterday because the voltmeter gauge was showing low level. I was also noticing the lighting in my gauges getting dim. They checked my charging system and the culprit turned out to be Mr. Alternator. The old one which was installed by a shop only lasted 2.5 years. I bought a rebuilt alternator that had a lifetime warranty and installed it myself. I was happy I was able to do it rather quickly (abou an hour maybe less). The cost was $124 plus tax plus $50 for the core which I will get back today.
Man, I love Ford!

 

look for battery to go next...low output failing alternator taxes battery.
best to replace in pairs so that old one does not cause new one to fail...

 

Agreed, been there, done that.

 

Guys,
Thanks for you wise advise but I want to know how to go about replacing a good battery. When the AutoZone guy checked the charging system, the battery checked out good. The battery is still under warranty (3 years into 7 year). Should I insist on getting a new one anyway?