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Discussion Starter · #1 ·
I started to try and diagnose what was wrong with all these radiator fans a few weekss ago as seen below in the old thread linked below.

http://www.uk-mkivs.net/forum/topic.asp?TOPIC_ID=37389&SearchTerms=,fans

Well RFSteel had the same problem aswell and he has given me his fans to diagnose and try and make a more permanent, and cheapper fix, as if these fans fail you are looking at a bill of ?300 to fix them and if you dont fix them it will also destroy yor air con pump, as RFsteel found out

heres the fan below

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the fan is held dclosed by these lugs

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and these lugs

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iew from the top

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to open these lugs need grinding off

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and these

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inside the fan is perfect no problems here

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prize this lid of carefully and note the spring in the middle

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once open leave the fan well alone the windings are easy damaged

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This bit is what we are concerned with I have now opened three of these fans and they have been in perfect condition, even the brushes are unworn

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this resistor is what is damaged, I have found a replacement, but it is too big to fit inside the fan so I need to repair this one

http://am001a0003.pwp.blueyonder.co.uk/images/fan10.JPG

this pic shows the corosion in the joint that cause the fan failure

http://am001a0003.pwp.blueyonder.co.uk/images/fan11.JPG

this shows it again

http://am001a0003.pwp.blueyonder.co.uk/images/fan13.JPG

here is the fault in macro view

http://am001a0003.pwp.blueyonder.co.uk/images/fan14.JPG

and again

http://am001a0003.pwp.blueyonder.co.uk/images/fan15.JPG

the joint is so weak it is no surprise that that some fans have failed in 20 thousand miles.

http://am001a0003.pwp.blueyonder.co.uk/images/fan16.JPG

I have not been able to conect these parts ,s solder will not take to the resistance wire , has anyone any ide on how I join these reliably.

http://am001a0003.pwp.blueyonder.co.uk/images/fan17.JPG
 

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Good stuff.

Just checked wiring diagram - Brown wire is Ground, Red/Black wire is full speed +12V, Red/White wire is slow speed +12V.

The resistor is just for slower speed, could replace with wire - although fan would run full speed.

Does the high speed work OK still? What value is the resistance?

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I would think that the resistor gets fairly hot during use - contributing to existing solder joint failing. So to resolder it might not be a good idea anyway. Don't know what the resistance wire is made from but might need to use silver solder and since it is thick would need high powered 50W or 100W soldering iron.

Maybe you could get it welded rather than soldered - don't know how easy this would be.

I would go for crimp connection - bare metal uninsulated crimp, or use the metal part from a screw type terminal block (cut the plastic away).

Or replacing the internal resitor with a wire link and using an external resistor in the red/white wire might be more reliable in the long term.
 

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To solder resistance wire you will need a suitable separate flux, try plumbers flux and plumbing solder and use a blow lamp (all from B&Q or similar). It is correct that the resistor probably gets too hot for this type of solder and may melt under working conditions. Silver solder, on the other hand, requires a very high temperature to melt but you may end up melting the resistance wire when you solder it.

Another possibility is spot welding using a capacitor discharge method , but this requires specialised equipment.

If I was doing this repair (and probably will be soon), I would use an aluminium heatsink resistor mounted externally, these resistors are available from RS and Farnell and are usually prefixed "HSA" ie a HSA50 is a 50W resistor. I can tell from the picture that the existing resistor is a low ohmic value and you will to be very careful measuring it to get the correct value.

Keep up the good work, this is very interesting and will hopefully lead to a fix for this particular problem
 

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COuld you not fit the replacement resistor you have (that will not fit in the fan cos its too big) outside the fan housing somehow. So long as you taped it well up, it should work....?
 

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Discussion Starter · #6 ·
Yes its a 0.9 ohm resistor, on my cheapo mutlimeter so 1 ohm should do it more or less,

You could get the resistor externally if you look at the early pics the fan cover has holes in it so come cloth covered cable should do it, anyone got part no's / prices for hsa50 from farnells?
 

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It is difficult to accurately measure low value resistances with a cheap multimeter - mine reads about 0.3 ohm when the leads are directly connected together. Would need to subtract this value from the reading to get the true resistance (then accuracy is +/- 0.1 ohm).

I would go for a slightly lower value (which will just make fan run slightly faster), because if a too high value is used the fan motor might stall and the power dissipation in the resistor will be very high - could burn out.

The aluminium clad type resistors are the most suitable - but the power rating is given for when it is mounted on a fairly large metal heatsink, if used unmounted then the 50W type is only rated at 12W, although the airflow from the fan will help cool it somewhat. So the resistor needs to be mounted onto the car bodywork or maybe a 100W or 200W type used.

The resistor can be attached to existing external wiring (if there are no other faults and the broken internal resistor wire is not touching the motor casing) :

Cut Red/White motor wire and insulate the end connected to motor, connect the other cut end of the Red/White wire to one end of the resistor. Strip some insulation off (but do not cut) the Red/Black wire and connect this point to the other end of the resistor.

Farnell resistor order codes :

345349 1 ohm 50W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=345349&N=0

3271195 0.33 ohm 50W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=3271195&N=0

345325 0.47 ohm 50W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=345325&N=0

345337 0.5 ohm 50W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=345337&N=0

3271201 0.68 ohm 50W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=3271201&N=0

652441 0.47 ohm 100W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=652441&N=0

652453 1 ohm 100W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=652453&N=0

272670 0.47 ohm 200W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=272670&N=0

272681 1 ohm 200W

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=272681&N=0
 

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HELP!!! my fans are not working on slow speed do the new fans work at slow speed or do i have a problem, also are all the fans the same (will the fans off a 18t fit my v6)
 

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Quote: posted by Neil-S on 04/10/2004 18:42:51

HELP!!! my fans are not working on slow speed do the new fans work at slow speed or do i have a problem, also are all the fans the same (will the fans off a 18t fit my v6)

Check the wires connected to the fan - if there are 3 (Brown, Red/White stripe, Red/Black stripe) as in the photos by andymac. Then it is a two speed fan.

Possibly a fault elsewhere like the thermal switch, but the fan failure seems fairly common.

Can connect fan directly to battery (preferably though a 30/40A fuse) to test :

Brown wire - negative

Red/White stripe wire - positive (for slow speed)

Red/Black stripe wire - positive (for fast speed)

The large fan should have label with part number : 1J0 959 455 X

where suffix X is the version letter (F, S etc.). Don't know if different versions are interchangeable, possibly different connectors.
 

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Discussion Starter · #10 ·
right neil 2 things are there any fuses blown on top of the battery? if so replace it?

now if all fuses are ok turn of all your accessories (especially the air con) now start the engine and open the bonnet, now the fans should not be running, now start the aircon/climate control and (make sure they are not on economy) now look at the fans again and they should be running on slow speed, if they arent it means either new fans or if your a confident diyer you can do my fix which I have shown above (I have finished the fans and will post the rest of the instructions tommorrow) as far as I know and was told by someone from german and swedish the fans from the 1.8 fans are different
 

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checked fuses and all ok did the air con test and fans kicked in and out fast no slow speed and 3 wires running to the fans, i am a macanic so diy repair no prob if you need a good meter or any kit to repair fans you have let me know i am only in skelmersdale. do you know how much the fans cost
 

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Discussion Starter · #12 ·
neil the fans are ?100 each (and you have to replace both of them), I would advise not using the air untill you get them fixed, as some people have found the excess heat can bugger the air-con compressor. As far as a fix I have doen much googling today and found out howto solder to the steelresistance wire, here is the fix

sand the end of the resistor wire down as here

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get some copper cable and some fine copper wire wrap the large caopper cable to the end of the resistance wire withe small wire as shown below.

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then solder as shown here (my soldering skills are rubbish)

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then refit into ceramic holder as here

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and here

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then put it back in its holder as here and trim the cables to meet, also giive them a little sanding so the soldering can take place

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heres the solder

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and here

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Discussion Starter · #14 ·
plumbers solder, with seperate flux I havent showed the piccies of it tacked back together as my father in law is doing it tommorrow, at the end of the day its worth a try before forking out 200 quid plus the dreaded.

The last time I did an experiment with replacement resistors and none worled to well, though you could replace the resistor with cable and they run at full speed but I dont see them lasting long if you do that plus there very noisy, though it could be a good temporary fix.

PS Dont bothere draining the coolant to get the radiator off I managed to get mine out by removing the radiator holder and I could just get the fan and carrier out
 

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Right, im trying to find the part no's for these. i can make out the part no. in the above pic, but are both fans the same ?

f not, what is the other part no. ?
 

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Quote: posted by MattyV5 on 25/10/2004 23:14:15

Right, im trying to find the part no's for these. i can make out the part no. in the above pic, but are both fans the same ?

f not, what is the other part no. ?

The part number for the other (smaller) fan is different.

The part number for the large fan shown in the photo will be the same but the letter suffix 'S' could well be different depending on model, year, connector type etc.

There should be labels with the part numbers on your fans - should be able to read them with a mirror and a torch without removing them. (Don't check when engine is still warm - the fans might start)

It might be good idea to ring a dealer with your VIN to check, as the part numbers are often changed or superceded. Then try to get them somewhere cheaper after.
 

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Ok

The problem is that the fans run for too long on some models, vw's fix is a modified fan control unit, but no it wont fix knackered fans it only prevents fans that are ok from becoming knackered, the dilema is the fans will probably only fail once in the lifetime of the car, so do you wait till they fail or do you buy the 'modified' control unit before it happens, if you repair the fans fair enough, who knows how long that will last, but its a dilema vw dont want to admit, if you go to buy a new fan control unit - its a new part number but if you buy new fans their part numbers are still the same - ie. the fans always have been ok for thier intended purpose just the old control unit ended up burning them out by running them too long without a break.

All sad but true! and wont help you, but I thoug it worth telling.
 

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Quote: posted by MattyV5 on 25/10/2004 23:14:15

Right, im trying to find the part no's for these. i can make out the part no. in the above pic, but are both fans the same ?

f not, what is the other part no. ?

The part numbers that I had for my V5 were;

1J0959455R

1J0959455S

Though if I remember correctly, I was told there are over 200 different rad fans listed on the VW system, so the above part numbers may not suit your V5
 
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