Oro

What is the spec'd charging voltage range for the 4ES (I assume same as other generations). I plugged in a new alternator today and it was 14.6V at idle and up. Seems a little high vs. other vehicles I have knowledge of, though not out of bounds. The crapulous rebuilt alternator failed in short order, and this is the (expected to be) crapulous warranty replacement. I think I will replace it with a known good OE used unit in a few weeks.

Back story:
18 months ago I had to replace the alternator and it was a "NITS" situation (need it this second). I ("she" ) couldn't wait to get a decent one shipped nor could I find a low-mileage take-off within driving distance from a recycler ("junk yard" as we called them before the PC era). I really knew it was a risk buying a rebuilt from a local auto parts store, but I did some homework and chose a Mexcan-sourced (vs. Chinese) rebuild from O'Reilly Auto for $200. And it worked great for... 18 months. As with most all of the failures from the big auto parts chains, the VR failed.

So folks, if you think you need a new alternator, take it to a good local shop and have the OE one rebuilt for about the same cost; don't delay and get in a "need it this second" situation. But if you do, do not go to the chain stores and expect to get a reliable unit. This is not my individual experience but widely known; this is just one more data point.

What I am going to do next month is get a take-off OE unit from a low-mile (e.g., <100k mile) wreck and replace the brand-new rebuilt, and sleep easier at night.

fortitude

INSPECT CHARGING CIRCUIT WITHOUT LOAD
HINT:
If a battery/alternator tester is available, connect the tester to
the charging circuit as per manufacturer’s instructions.

1. (a) If a tester is not available, connect a voltmeter to the charging circuit as follows.
   1. (1) Disconnect the wire from terminal B of the alternator, and connect it to the negative (−) tester probe of the ammeter.
   2. (2) Connect the positive (+) tester probe of the ammeter to terminal B of the alternator.
   3. (3) Connect the positive (+) tester probe of the voltmeter to terminal B of the alternator.
   4. (4) Ground the negative (−) tester probe of the voltmeter.
2. (b) Check the charging circuit as follows.
   1. (1) With the engine running from idling to 2,000 rpm, check the reading on the ammeter and voltmeter.

Standard amperage: 10 A or less
Standard voltage: 13.2 − 14.8 V

INSPECT CHARGING CIRCUIT WITH LOAD

1. (a) With the engine running at 2,000 rpm, turn on the high beam headlights and place the heater blower switch at ”HI”.
2. (b) Check the reading on the ammeter.

Standard amperage: 30 A or more

Htony

I never had problem with rebuilt alternator/generators. Dealers sell remanufactured ones too. Bad battery, bad charging circuit(often embedded inside alternator) can damage alternator or battery, etc. Most important is good grounding. Always use common analog meter or if digital meter is too sensitive due to high input impedance. Digital meter can even read of voltages off your two finger tips. I back is in EE (retired PE, class of 1960) Actually rebuilding something like alternator is not that hard.

Oro

Thank you fortitude, that helps. Next weekend I will put it in the garage overnight and test more thoroughly per that. Looks ok per those specs for now, but I will test directly to the unit with my meter.