1984 300D new alternator and battery still having problems with it being dead after driving it around town for a few hours, will come back to the car and it will be dead. With the car under load im getting 14.3 volts, as soon as I turn my A/C on it goes to 13 volts is that normal? Didn't know if I potentially have a faulty compressor?

A drop like that when turning on the a/c indicates poor voltage regulation or a weak connection. Check the connectors on both ends of the wires leading from the alternator to the hot starter post. The crimp on these connectors sometimes get loose. If the connections are solid, it wouldn't cost much to just stick a voltage regulator on it and see what happens.

Hope this helps.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

Is this at an idle? If so you are doing good. With this voltage readout I suspect bad battery connections or bad battery

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1977 300D Lost coolant while someone else was driving
1983 300D Can't run without oil
1985 300SD (gone but not forgotten)
1990 300TE 4matic Sold
1991 Yamaha Venture
1975 Kawsaki 250 triple
1974 Honda 200CL
1951 8N Ford
2008 Wildfire 650C

Put in a cigarette lighter voltmeter and monitor the voltage as you drive. If the volts stay in the range you describe the problem is likely a draw on the battery with the key off. You'll have to pull the negative cable with the key off and put an ammeter between the post and the cable to see if there's a draw. If there is, pull the fuses one at a time until you figure out which circuit is shorting out.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13