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Old 31st May 2010, 22:29   #1
HarryM1BYT
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Default Replacement Resistor for Radiator Fan

Thanks to a posting on the forum, I have discovered that my cooling fan is not working properly. It is a Mk2 with a two speed fan using a resistor in series with the fan to provide the lower speed. Mine, when the a/c is on, cycles constantly on and off full speed unless the car is moving fast enough - which according to the posting means the resistor has probably gone o/c.

This a rather high wattage unit and the suggestion was that a replacement might be available from Maplin. That might have once been true, but not anymore. I have managed to track one down from a company called Rapid Electronics. Their item # 62-8174 is a 0R47 100 watt unit, a little over £10 delivered.

http://www.rapidonline.com/
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Old 31st May 2010, 23:02   #2
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I would stick in purchasing one from Jules (Trade member on here)
His come with sleeves etc and drilled out on base ready for fitting and are the correct wattage required etc.
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Old 1st June 2010, 07:05   #3
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Default Resistor spec

Need a resistor upgrade myself & came across this thread whilst looking for info.
Yes it does seem a good idea to source the "kit" from Jules but I have a garage full of thing like nuts, bolts, crimp fitting etc so only need a resistor.
I know it needs to be 100w but what other specifications does it need to meet and would this do the job equally well
http://cgi.ebay.co.uk/Tyco-High-Powe...93f403fe347b62
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Old 1st June 2010, 07:50   #4
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Quote:
Originally Posted by xion2000 View Post
... would this do the job equally well?
It's only 0.1 ohms Graham which is far too low to have any effect on the speed of your motor. You need to know the resistance of the OEM item or Jules' replacement.

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Old 1st June 2010, 07:59   #5
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Default Upgraded Fan Resistor

Did a bit more reading up and found out it needs to be 0.3-0.5 ohms resistance and at least 100 watts power rating.
I've ordered one of these from RS. Part Number 188-065,100W R47, which is 0.47 ohms. It's an aluminium clad module with a lot of meat on it. It's surprisingly hefty and should last the lifetime of the car.
http://uk.rs-online.com/web/search/s...duct&R=0188065
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Old 1st June 2010, 08:03   #6
xion2000
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Quote:
Originally Posted by SD1too View Post
It's only 0.1 ohms Graham which is far too low to have any effect on the speed of your motor. You need to know the resistance of the OEM item or Jules' replacement.

Simon.
Thanks for the info Simon, I'd ordered before I'd seen your post but had already found out it was not suitable. I read on another forum that the one I've ordered is suitable (hopefully)
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Old 1st June 2010, 09:36   #7
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Graham,

If the resistor you've ordered dissipates 50 watts in use, then it should drop about 5 volts which sounds encouraging. Let us know whether or not you're successful. A £3.46 fan repair will be the cheapest method yet!

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Old 1st June 2010, 21:11   #8
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Come on guys stick with the Jules resistor ! Support your local small businesses and fellow enthusiast ! Jules spent a lot of time with these and for what he charges they are a bargain ! just think of the help he gives everyone on here for not a penny I know who I was supporting when i ordered mine !

(Having said that this is just my opinion and what the heck do I know lol )
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Old 1st June 2010, 21:45   #9
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Jules sells his units on eBay. Just do a search for 'rover 75 fan resistor' you can't miss it. All the hard work's done for you. Remember buying a basic resistor is only the start of the task. If you don't the connections right, you can be wasting money.

TC

Last edited by T-Cut; 1st June 2010 at 21:48..
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Old 1st June 2010, 22:41   #10
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Thanks TC JDC and TIM
But for those of you buying just a basic component beware:
some only have flimsy terminal lugs only for use near circuit boards.

Mine are Genuine RS and you can plug/solder a Lucas connector straight on to them


But hey it's a free country so buy where you like !!

"Caveat emptor" as Zeb says
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[SIGPIC][/SIGPIC]


Newbies do now!!
1. Plenum drains..all 3 or 4 year dependent
2. Cooling fan..All speeds functioning
3. Bonnet cable divider block
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