2002 E46 325i, Alternator problem?

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  1. 2002 E46 325i, Alternator problem? 
    #1
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    hello

    Could anyone tell me what the voltage should be coming from the alternator when the car is running?

    Im having warning lights appear on the dash airbag/hood/traction etc. when i turn the lights on some go on/off its very odd!

    I changed the battery last week and drove approx 150 miles. when i got back and opened the boot smoke was pouring out of the battery!!

    I have put a meter across another new battery and with the car running i have 17.9v running through it. This goes down to 17.3v with the lights and aircon on.

    Is that normal?? any help suggestions would be great.
     
     

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    Fook me that's too high . Should be around 14V when running, so I reckon you have a faulty voltage regulator in the alternator.
     
     

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    Your alternator is knackered,

    Even possibly the new battery too, would be a good idea to get it tested.If the battery has got removable tops to check the water level then would be a good idea to have a look. May have boiled it dry.
     
     

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    luckily the cars not moved since putting the last new battery on. Is the voltage regulator something that can be changed? or am i better off just getting the whole thing replaced?
     
     

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    IIRC the voltage regulator can be changed on its own.

    And try not to use the car until you've sorted the alternator or you could end up damaging the ECU

    Whats the voltage with the engine off?
     
     

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    You can get a new alternator for pretty cheap these days, http://www.eurocarparts.com/alternator

    But you can also get the regulator separately, don't think I'd bother though. http://www.realoem.com/bmw/partgrp.d...id=47604&hg=12
     
     

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    Quote Originally Posted by shamM3 View Post
    IIRC the voltage regulator can be changed on its own.

    And try not to use the car until you've sorted the alternator or you could end up damaging the ECU

    Whats the voltage with the engine off?
    Is the regulator something i can change? i'll do a search for a DIY and see what comes up.

    Is the regulator a standard part or are there different alternators on the E46's?

    With the engine off im getting 12.5v
     
     

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    Quote Originally Posted by jay146 View Post
    Is the regulator something i can change? i'll do a search for a DIY and see what comes up.

    Is the regulator a standard part or are there different alternators on the E46's?

    With the engine off im getting 12.5v
    I'd agree with Ronnie, change the whole alternator they don't cost much

    You can change the regulator fairly easily its only held on with a couple of screws but you still need to remove the alternator from the car.
     
     

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    Quote Originally Posted by shamM3 View Post
    I'd agree with Ronnie, change the whole alternator they don't cost much

    You can change the regulator fairly easily its only held on with a couple of screws but you still need to remove the alternator from the car.

    Thanks for all the help i think i'll change the whole thing. Im guessing the new battery may also have gone :O( I charged it before putting it on the car last night. I checked the battery drain and it was around 40ma. This morning the battery was showing 11v.
     
     

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    New batteries come with guarantees so get it swapped for another one. Its safe to say that any battery that smokes has had it.

    Got to be careful around them as well just in case they go bang, not nice getting acid in your face
     
     

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