alternator querie
02-09-2005, 01:02 AM
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alternator querie
ok, here goes nothing.... i realize many will scorn my non-purist project but i need advice and i am willing to endure it.... about 9 months ago i gave my 86 420sel a heart transplant with my 83 300sd with a failing shell being the donor... all had been bliss, not complete (annoying warning lights being the thorn) but the transplant gave a wonderful engine a nice place to breathe... that being said, the gremlins attacked.... within two days the license and marker lights refused to continue (0.10V going to each), then the driver door courtesy lamp and dome lamp called it quits (getting power to both leads, no ground).... being that i had not changed anything i searched the service manual, to no avail, then the alternator and battery went... i assumed purchase of both would solve the issue but no.... in searching threads i noticed that the ovp may be the problem or (and this one scares me) it could be the fact that the 420 engine came with an 80 amp alternator while the 300 has a 65 amp.... opinions please 
02-10-2005, 08:05 AM
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1989 560SEL, 1999 S600, 2005 S600, 2008 S550 4Matic
You are on the right track. The 300SD came with a 65 amp alternator while the 420SEL came with an 80 amp alternator.
.... thanks for the input...
02-11-2005, 01:29 AM
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1989 560SEL, 1999 S600, 2005 S600, 2008 S550 4Matic
I'd replace the alternator with one with the proper amp rating. You really don't want to mess with the electrical system in a Benz. Some components may get damaged over time and cost you an arm and a leg. You can get a used alternator for your 420SEL from eBay or from your local junkyard.
