W203 Alternator - anybody removed one?

[colin_d]

A problem exists on my C220 CDi, the dash is lit up red with battery/alternator visit workshop. The car is starting fine at the moment, the belt is turning the alternator, so i'm guessing the alternator is not to good. Can these be tested on the car, or is it best to remove it & take it to a specialist to test?

 

[tolly]

alternator went on my w202, the battery light was on like yours
put a multy-meter on to your battery to see whats the voltage with the engine running. should be around 14v if the alternator is working
OR
put the multy-meter on to your alternator with the engine on to see the amps output should be around 300, im not too sure tho depends on the motor but the output should be on the alternator itself

 

[230K]

alternator went on my w202, the battery light was on like yours
put a multy-meter on to your battery to see whats the voltage with the engine running. should be around 14v if the alternator is working
OR
put the multy-meter on to your alternator with the engine on to see the amps output should be around 300, im not too sure tho depends on the motor but the output should be on the alternator itself

You will not have a 300 amp output alternator or indeed a multi-meter capable of measuring 300 amps.

The 14 volts info is spot on though.

The alternator regulator/brush pack can be replaced easily on alternators also the free wheeling pulley can slip and cause problems

Hope this helps

230K

 

[colin_d]

OK, Ive just been outside, removed a filter from above the battery, and it reads 11.8ish volts basic, rising to 13.6-13.8 Volts when on tickover. I cannot easily get to the alternator to check any further, but does this indicate the alternator is OK?

 

[colin_d]

I'm thinking it may be that the battery is on its way out? It appears to be the origional & its 6 years old. Any thoughts?

 

[BlackC55]

Expect 14V at idle or there abouts for a functioning alternator.

What is the voltage across the battery when not running after leaving it overnight?

 

[colin_d]

Just been out & taken a reading accross the battery 11.79 Volts. Did not start engine, it was only started yesterday morning to take the readings ive posted here.
What does this mean?

 

[tolly]

You will not have a 300 amp output alternator or indeed a multi-meter capable of measuring 300 amps.

Hope this helps

230K

sorry
didnt mean the amps
cant remember the name for this yoke but its a resistance value or something like that (cant remember the name in english, im russian) but its on the alternator and its given value....
anyways the alternator isnt your problem as you already know

 

[mrblubo]

Just been out & taken a reading accross the battery 11.79 Volts. Did not start engine, it was only started yesterday morning to take the readings ive posted here.
What does this mean?

hi, how did you solve problem - I have the same one at the moment with the same car...
thanks

 

[qainat]

Alternator woes

For the second time the battery has run down. So took it out (and yes I followed the disconnect and reconnect order) and recharged it. Measured voltage across the battery terminals with the vehicle running and it read around 12.3 V. This was on a freshly charged battery, so I guess this indicates a faulty alternator as it should read around 14.5 V. Am I right?

 

[brucemillar]

Well you should see 14+ vdc with the engine running at 2.5k. So it does look like your alternator is toast. Not sure if it has a changeable regulator. If yes (bolted on the back) that could save you big money.

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