Bring the alternator into Autozone to have it tested to verify that it is bad. Have you done that with the first 3 alts?

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Yeah, they test em to verify before accepting them back.

What brand of reman alternator is autozone providing? My experience has been the "OEM" brand remans are absolute crap. One lasted a year, another barely 2k miles.

You've checked and checked and checked the cars system, the one constant remains the autozone source. The charging system is very simple on these cars. 4 alternators in a row seems crazy, but then again its 4 alternators in a row all from the same source.

Id consider changing it up. Id buy either a genuine bosch reman from PP or similar (in boh cases the solution to my bad alternators), or id pull a original alternator from a junk car and see what either do

__________________
This post brought to you by Carl's Jr.