Charging Issues

Hey guys I got a 91 caprice classic with a 305, 140k miles. The battery light came on ( the one to the left of the gauge cluster) and my lights started to dim while I was on the highway doing about 70. I was wondering if you guys think it would be the voltage regulator or this Alternator. Im hoping its the regulator because I dont want to spend 100+ on a new alternator.
Thanks for any adivce or input.
New to the forum

Hey guys I got a 91 caprice classic with a 305, 140k miles. The battery light came on ( the one to the left of the gauge cluster) and my lights started to dim while I was on the highway doing about 70. I was wondering if you guys think it would be the voltage regulator or this Alternator. Im hoping its the regulator because I dont want to spend 100+ on a new alternator.
Thanks for any adivce or input.
New to the forum

Sorry, sounds like an alternator issue.

The armature has wires that pass through the steel pole pieces and the insulation surrounding these will eventually deteriorate and begin to fly out. When this happens, the wire will touch the pole piece and the the insulating varnish will chafe against the pole piece. It then shorts, causing the alternator to stop charging. This sort of failure makes itself known on highways at higher speeds, due to centrifugal force causing that wire to touch the pole piece. Around town, it'll work fine.

Silicon, what happens inside the altenator when it just suddenly stops working alltogether at any random engine speed and refuses to charge at all? Same thing just more drastic?

Silicon, what happens inside the altenator when it just suddenly stops working alltogether at any random engine speed and refuses to charge at all? Same thing just more drastic?

Any number of things - diodes, the rectifier block, voltage regulator, open armature, brushes, loose or missing drive belt, etc. If it just simply quits then get a new one - as long as you've verified the alternator is the cause and not an effect of a different problem.

Also keep in mind that only the older Delco 10SI and 12SI alternators are rebuildable - the ACDelco/Delphi CS series are not.

Also keep in mind that only the older Delco 10SI and 12SI alternators are rebuildable - the ACDelco/Delphi CS series are not.

I would assume that the mid-late 80's Caprices such as yours and mine ('84) come with the CS series correct?

I would assume that the mid-late 80's Caprices such as yours and mine ('84) come with the CS series correct?

The CS started use in 1988 - 1987 in some cars. Mine has a CS130, yours should have a 10SI.

Oh cool, thanks! That information will come in useful in the future when my altenator does decide to go.