Alternator problem ? - PeachParts Mercedes-Benz Forum

Piratejason · #1 03-15-2007, 08:25 AM

Okay, car is 1985 300D - turbo with over 280k on the clock.

For the last couple of weeks the fuel reserve indicator, batt. light, brake indicator and one other light have been lit while car is operating. Batt. voltage has maintained above 12volts and occasionally while accelerating gets up to 12.4volts.

I have replaced and adjusted to specs. the alternator belts.
I have replaced the voltage regulator with a Bosch from MercedesShop.

Is my alternator toast? I never see voltage above 12.4
Any tricks to try - dousing with contact cleaner, etc. ?
If replacement is needed any recommened ones that have correct pulley and don't cost more than $150 ?

Thanks,
Jason

pawoSD · #2 03-15-2007, 03:56 PM

You usually have to transfer the pulley from the old to the new with these, its just the way it is. Also, it should be producing more like 13.8-14.0 volts...if its at 12-12.4 then the alternator is doing nothing and its killing the battery. Check all connections for corrosion and the alternator probably needs to be replaced as well.

pj67coll · #3 03-15-2007, 08:22 PM

Does your car have an electrical cable from a plug on the back of the alternator running back towards the battery? If so remove the plug and check to be sure all the wires inside that cable (three on mine) are solidly connected to the plug. One of mine was broken off inside the plug so I'd have never noticed it and the other was about to break. Fortunately my new indy spotted it and rewired them for me. I'd had very similar symptoms to what you are having recently but now they have all cleared up.

- Peter.