Patient: '83 300D, 330,083 miles. Voltage regulator is new from 28 September, 2500 miles ago. Battery was replaced at that time also. Prior to that the car had an overcharging problem which fried the battery and headlights.

I did some checks today after tightening my squealing alternator belts. 12.58 VDC with the engine off. Engine running at idle with no load gradually came up to over 17 volts. Turning on headlights and blower pulls it down to about 12.5 at idle, but revving the engine gets erratic results ranging from mid 14's to 16. I checked AC voltage and got 36 VAC at the battery terminals with no load and 28 with headlights and blower on. I've also noticed that the battery light in the dash never illuminates.

I'm thinking its time for an alternator, but wonder if there is something else at play here. Could this be some sort of oddball wiring problem? I'm open to suggestions.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

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