[W126 Coupe] alternator...

[Sharan Bains]

Thought I'd share an experience with the alternator on my 190E 2.3-16 Cossie 
- the dash warning lights were not coming on at ignition pos II and the 
alternator would drain the battery whilst the car was stationary overnight. 
That's without the car being driven - with a fully charged battery and the 
car parked up for the night, the alternator would have the battery FULLY 
drained by the morning.

Well, Sat morning, I changed the alternator. Got a good used one for 40 quid 
and changed it out. A w126 alternator change takes less than 5 mins...but on 
the m102 16-valve, the lower 17mm bolt is actually released by removing the 
17mm nut on the rear...with the compressor underneath and headers behind all 
in the way, that was not fun ! And you do have to remove the entire thing - 
the alternator has a plastic and metal cover ont he rear held on by another 
4 8mm bolts....so simply removing one bolt and swinging the alternator to 
one side was going to be just as awkward.

But once changed...voila ! Perfect - dash warning lights back on and over 14 
volts charge when engine running. The Cossie has it's own stock MB fitted 
voltmeter down in the centre console, so it's a good indicator.

I thought about changing the regulator/brushes, but those alone cost around 
40gbp from MB and given the hassle to remove the alternator on this engine, 
Ithought I'd go with a good used one.

The reason it went bad and why I suspected it...the car was at my bodyshop 
having the front wings refurbished and they decided to steamwash the engine 
with a pressure washer. Not a good thing for alternators...

Why people steamwash engines is beyond me...better ways to keep an engine 
bay clean. MB UK have a policy at all their workshops which bans 
steamwashing of engine bays.


talbir