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Thread: Overheating bora. Fan not working

  1. #11
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    Quote Originally Posted by WhO View Post
    Hmmm had a closer look at the fans today because the car started overheating, looks like the larger fan isn't working at all anymore. If i spin it manually it'll sometimes spin up for brief period then stop.

    Anybody recommend anywhere in Adelaide i could get a set of fans?

    Cheers,
    Robert

    Tim at Volkstorque or Volksfactory would be my first phonecalls. Just confirm it's not the fan controller near the battery first or the fan switch in the radiator.

    Gavin

  2. #12
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    Well after a bit of fiddling i've got the large fan working properly again... for how long im not sure but i'll check it every day and keep you updated to see how long the fix lasts.

    Its a bit crude of a fix but after reading the thread http://forums.tdiclub.com/showthread...hlight=vag-com (excellent excellent source of information) i decided to try a few things before pulling the fans out.

    After confirming on my partners bora that both fans should come on together on both low and high speeds i was fairly satisfied that on mine the issue would be with the large fan.

    After confirming that the large fan was infact getting voltage thus eliminating anything on the car side i tried tapping the fan whilst it was meant to be running. No dice so i tried pulling at it gently and hey presto it would very gently try to turn. This gave me the impression a brush may be stuck and not contacting the comutator properly or gunk may be in there disrupting the contacts.

    Possibly not the greatest idea / fix (but used to worked on R/C cars so i figured worth a shot), i then pumped the fan motor full of wd40 hoping that it might be a sticky brush or some gunk on the comutators. After this the motor still didnt really want to work so enter me firmly but gently hitting it with length of wood. After a good bit gentle persuasion it slowly jumped into life and progressively got stronger and stronger.

    The fan now runs strongly on both low and high speeds, i reckon i'll keep the wd40 in there for a lil while to try and clean out the gunk and then i'll pump it full of contact cleaner to clean it up.

    A note on wd40 is its non conductive so safe to use around electronics, thus why back in the day i used to use it on remote control servo's if they ingested water.

    Hopefully this solves my issues! If not i'll be pulling the fan out and apart to properly diagnose it.

    Cheers,
    Rob

  3. #13
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    Yeah mate thats right its the goods, anyway does sound you have a bad point in your fan at least one anyway, these fans do in fact overheat the fusebox on the battery. The fuse box is the quick fix but in the end its normally the shorting fans thats the issue, i remember tripping over plenty in the VW warranty cupboard
    good luck
    Jmac
    Alba European
    Service, Diagnostics and repairs. Mobile Diag available on request
    Audi/VW/Porsche Factory trained tech 25+ yrs exp
    For people who value experience call 0423965341

  4. #14
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    Looks like my issue is only semi fixed. Big fan is working intermittantly, sometimes takes a little flick to get it spinning, when the weather cools down i'll take the fan out and pull it apart, untill then fingers crossed it keeps working!

    Edit: definitely not working now, go for a drive and it stops working i guess from the road vibration. If you push it towards the radiator on the shaft it'll run but release pressure and it stops.

    I'll pull it out asap and take photos of it all. Anybody know the easiest way to get the fans out? From the bottom i'm guessing?

    By any chance do you happen to know what the fans motors are worth Jmac? Might just end up getting a new one if they're not too steep
    Last edited by WhO; 10-01-2010 at 10:56 PM.

  5. #15
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    All Fixed. Pulled it all apart today and ended up finding that two of the brushes were stuck retracted back thus not contacting the commutator. After cleaning everything up and ensuring they slid properly it all worked like a charm

    Basic guide of what i did: (no pics yet as i cant post attachments)

    1. Put the car up on ramps / with the front in the air. Note if you use ramps take out the 4x T25 torx bolts attaching the splash guards to the front bar off now because to access them its far easier if you can turn the wheels

    2. Following the guide here on vwvortex http://forums.vwvortex.com/zerothread?id=2368291
    I put the carrier into service position. To remove the thermo's you only need to follow the basic steps, no coolant needs to be drained or anything like that.

    3. Unclip the plugs going to the radiator fans, two in total. These come apart fairly easily after you remove them from the holder on the shroud. To remove them from the shroud gently twist them off then they are disconnected by pulling on the release tab whilst gently pulling the halves apart.

    4. Undo the 4x T27 torx screws at each corner of the radiator, i found a 3/8 drive ratchet with the torx attachment attached handy for getting into the tight space on the upper screws.

    5. With the torx screws out the radiator fans and shroud will be just sitting on the radiator, gently whilst under the car push the front carrier forward about 2 inches, it may be wise to have a helper hold / pull the carrier away or assist at this point just to ensure the carrier doesnt try to fly off! I however supported the carrier with my knees. Once you have gained a bit more clearance move the radiator fan/shroud assembly away from the radiator and manourver the drivers side (smaller fan) down past the a/c lines. The fan / shroud assembly i found is easiest to get out like this dropping it out at an angle drivers side first.

    6. With the rad fan / shroud assembly out undo the 3x 10mm nuts holding the inoperational fan to the shroud and take the fan/motor assembly off the shroud.

    7. Using a dremel cut the tabs that are bent over the motors backing plate to allow the backing plate to come away from the motor.

    8. In my case two of the brushes were stuck retracted, a bit of wd40 later and they were free and sliding just fine.

    9. lightly clean up the commutator with fine emery paper to give the bushes a nice new surface to contact

    10. clean the whole motor, bushes, windings etc with contact cleaner but try to avoid spraying the bearings.

    11. Re-assemble the motor and upon refitting the bearing plate gently clamp it down and then glue it down with either a high temp epoxy resin or as i used Sellys Knead It Metal.

    12. Work back from step 6 backwards but dont forget to test the fans operation before putting everything back together. This can be done by
    (copied from http://uk-mkivs.net/forums/t/59897.aspx)
    Reconnect both fan connectors, if still disconnected, and disconnect the 3 pin connector from the radiator fan thermo switch.
    Bridge contact 1 and contact 2 with a short piece of wire, the fans should run at low speed.
    Switch on ignition, bridge contact 2 and contact 3 with a short piece of wire, the fans should run at high speed.
    Switch off ignition, reconnect thermo switch connector.

    To identify the connector pin numbers, hold the connector facing you with connector latching mechanism at 2 o'clock, pin1 is then at 12 o'clock, pin 2 at 4 o'clock and pin 3 at 8 o'clock.

    13. If it all works finish off with a nice cold drink... especially when its 43 degrees out!!!

  6. #16
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    I wish I found this thread earlier! been without air con for nearly a month now - just went and checked the fuses. One was melted. Changed it and all back to good!

  7. #17
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    Yes when you read the Vortex link in thread posted by Graeme86 right through you will see that the fans are actually quite robust and will last for years. It is usually only the internal resistor that is broken and that stops the fan from working on the low speed. In my case the problem was exactly as described in the Vortex thread and as I said above the recommended fix has been working fine ever since.

    However VW just go in and replace the whole fan unit (at considerable expense) when it isn't really necessary. The problem here is that it doesn't fix the design error and the new fans will fail in exactly the same way.
    2001 Bora 4 Motion Sport now used by number two son
    2011 Skoda Octavia Scout now with Underground Performance tune
    2010 Jetta 125 tdi dsg for the misses - Impressed
    2006 Polo GTI - Enhanced by some of Gav's magic - Absolutely loving it

  8. #18
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    These are some great tips for VW owners! You might've saved a few people in excess of a thousand big ones. Good stuff!
    2000 Mk IV GTI


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