1st Gen R50 Cooper Alternator?

Discussion in '1st Generation: 2002–06 R50, R53 & 2004–08 R52' started by interzonearts, Jul 2, 2015.

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  1. interzonearts

    interzonearts New Member

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    Hello guys. We have a 2003 cooper with about 70k on it and it's served us well.
    The charging light came on tonight and at the same time it did start surging a lil bit at idle. Not much but it doesn't go below 1k rpm and doesn't go pass 1.8k (unless i press the accelerator of course:) )

    My guess would be the alternate is failing and the computer rises the rams to get enough voltage??

    Or is it something else?
     
  2. CHKMINI

    CHKMINI Club Coordinator
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    Check the jump stud connection on the firewall. These have been known to come loose and/or corroded and give the same symptoms as a bad or failing alternator.
     
  3. MCS02

    MCS02 Moderator
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    What CHKMINI sad and. How old is the battery? these cars do some very strange things if the battery is bad. Have the battery tested at a parts store. It could be a bad crank pull but start with the connectors and battery first.
    Of course it could be a bad alternator.

    First post! Welcome to MA! Being this is your first post all advice is free. :D
     
  4. interzonearts

    interzonearts New Member

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    Thank you for your replies. So i finally had time to look at it and it looks like all the connectors are ok. The battery is 4 years old but i don't think it's the problem.
    I checked the voltage at battery terminals and i got 12.5 v when off but drops to 11.5 when the car s running.

    I tried do measure the voltage by the alternator terminals but the space is so tight there and i could see/get to just one terminal and it was almost 12v when off and about 11v when it was running between the terminal and the alternators housing.
     
  5. Nathan

    Nathan Founder

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    Welcome, thanks for joining Motoring Alliance, the FUN and Friendly MINI Community.

    I'd check the battery first before swapping out an alternator. These are very fickle cars when a battery is not at it's best.
     
  6. vetsvette

    vetsvette MINI Alliance Ambassador

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    When the car is running you should see ~14V.
     
  7. Canusrufis

    Canusrufis RMW Powered R53
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    #7 Canusrufis, Jul 6, 2015
    Last edited by a moderator: Jul 6, 2015
  8. Noah

    Noah New Member

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    Sounds like the alternator to me. It seems to me that if the battery were bad you wouldn't have 12.5v with the car off. I've replaced the alternator in my MINI several times (don't ask) and it's not too difficult but requires a bit of patience.

    One thing—does your power steering work? I'm not 100% sure about this, but I think the charging cable of the alternator runs through the electric power steering pump, so you might want to make sure that connection is good as well. It's a pain to access, but seems worth a look if the power steering isn't working.
     
  9. CHKMINI

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    Battery.....4 years is on the brink of replacement for these cars
     
  10. interzonearts

    interzonearts New Member

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    I didn't have it in me to deal with it so far but i'm fixin' to it. The power steering works, all the fuses are OK and the battery tested fine. It must be the alternator since it's not increasing voltage at the alternator's terminal when the engine's running.

    Anyways i looked at the service manual and it calls for removing the right front wheel and the intake manifold. I feel a bit apprehensive about the manifold. I've done work on diesel engines before but not on gassers so i wonder if there is anything that i should pay particular attention to so i don't mess anything up.
     
  11. Canusrufis

    Canusrufis RMW Powered R53
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    I've got an r53 but helped another r50 owner R&R their alternator. I don't recall having to remove the intake manifold. I had to drain the fluid to get one of the hoses out of the way but was able to find the 3 bolts holding the alternator and rotate it out. It took me longer to bleed the fluid than change the alternator.
     
  12. interzonearts

    interzonearts New Member

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    I hoped someone would say something like that. So i remove the wheelwell, take the serpentine belt off, disconnect the upper radiator hose and swap the alternator?
     
  13. Canusrufis

    Canusrufis RMW Powered R53
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    The wheel well wasn't removed either. Just the radiator hose over the alternator remove belt and bolts. It was easy to me. Again took me longer to bleed the air back out of the coolant. The connection to alternator was tedious but just take ur time. You can do it.
     
  14. interzonearts

    interzonearts New Member

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    I decided to give it a try today. I managed to undo the lower screw without busting any knuckles even though i could barely fit my hands in there.

    I did get stuck on the belt though. nothing i have i could use to release the tensioner. I guess i will have to order that special tool.

    Unless there is a trick to do it that without the special tool you guys know of.
     
  15. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    Put a 16mm socket on on the pivot bolt for the tensioner
    Stick a small allen wrench, a nail, or some other short, strong thing with appropriate diameter into one of the holes in the tensioner that the special tool would use.
    Using a long pry bar as a lever, with the socket as a fulcrum, lever against the allen wrench or whatever, to move the tensioner the same way the special tool would. Then stick a pin in the tensioner hole. Helps to have a second set of hands helping with all this... wear gloves, pinches happen.

    The tensioner tool is much easier... but I did it this way several times before I owned the tool. Takes some trial and error with things slipping out of place, but you'll figure it out. You could also use some tape to hold the socket and the little wrench or nail in place...
     
  16. interzonearts

    interzonearts New Member

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    It was the alternator

    So i put the new alternator in today. It was not all that hard with just the upper rad hose removed. After i started the car again the idle was still elevated but after i drove around the block and the battery recharged a bit it went down to normal.

    Thank you all for help.
     
  17. Canusrufis

    Canusrufis RMW Powered R53
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    Excellent! Happy endings are good.
     
  18. interzonearts

    interzonearts New Member

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    Is there any sense in trying to rebuild the old alternator just to keep it as a spare?
     
  19. Nathan

    Nathan Founder

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    Thanks for following up and letting us know how it went.
     
  20. MCS02

    MCS02 Moderator
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    For me it would depend on the price of the rebuild.
     

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