I'd like to upgrade the alternator of my 1989 300E and I am looking at used products. Which other Mercedes models have the higher capacity alternator that can replace the lower capacity pre-1990 models of the 300E?

For instance, will an alternator from a 1992 190E fit and be the better alternator?

Thanks,
Paul

First off, I'll assume your 300E has the M103 motor.

My 126 car also has an M103 motor.

I needed a new alternator last September and instead of replacing with the 80amp Bosch AL66X - 80 amp, I installed an AL166X - 100 amp alternator which is supposedly for diesels. My 103 likes it just fine. I see 14.30 volts at first start-up in the am. Never saw that with an 80amp alternator. The AL166X fit exactly as the original alternator that was replaced.

I'm not saying this will fit your application, just sharing information.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

I don't know the answer to your question, but the odds are very high that you don't need an entire alternator, only a brush pack. On the back of the alt. there is a pack with a round semiconductor bulge that is held in with two screws. If you pull that out, you will probably see that the brushes on it are worn down to a nub. If so, you can replace that brushpack for $15 by clicking on the Buy Parts or Fastlane above. It takes five minutes to change it.

Hope this helps,

Larry's point is well taken. It takes me more time to setup for this job than to do the job. It's a very easy task.

First consider Steve Brotherton's words in the following thread.

76 240 D Electrical problem - need help

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Actually I'm looking for a larger capacity alternator that would hold up to the electrical demands during winter driving. I have the older 70A alternator that doesn't quite provide enough juice for winter driving (heated seats, lights, stereo, heating system, etc). I understand that post 1990 alternators for the W124 cars are much superior. However, how similar are the alternators across the MB model range - say from 1989 to 1995? What other Mercedes alternators would fit my '89 300E (M103 engine)? Or do I just stick with the M103 fitted alternators?

Thanks,
Paul

I would recommend your local starter/alternator shop. They will tell you exactly what you need to know and probably walk over to a shelf and set a reasonably priced unit on the counter.

Good luck,

Yes the 92 year model will be a significant improvement. Look at the back of the alternator. If the power output wire is bolted to the unit you are looking at a high output device. If the power is output with a push on spade terminal it is low output. The rating isn't even as significant. The better alternators are better in that they put out large portion of their rated output at idle speed where as the lower performance ones take 1500-2000 rpms to get 70% or more output. This can make a difference of 50amps at idle speed.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Been there, done that:

Installed a 143A alternator in my W124 (86-95E-class) - with photos

I have a 150A alternator in my 300D and E500 right now. Complete bolt-in after you swap the pulley, re-clock the alternator body if required, and install larger cable to the battery. Donor cars are late (1996-up) M119, M120, and M113 for the 143A and 150A.

DO NOT have an alternator shop re-wind your stock alternator for more output!!!

__________________
Dave
Boise, ID
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