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Old 9th March 2021, 09:26   #11
AndrewJames
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Originally Posted by SD1too View Post
Just to let you know Andrew that your temperature gauge will steadfastly remain at the nine o'clock position for any coolant temperature between 75 and 115 degrees C! It will therefore give you a false sense of security so ..... as Arctic says:




Simon
Hi Simon,

Really? I remember reading it was a bit of a vague measurement but I didn't realise it was as bad as that!
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Old 9th March 2021, 11:20   #12
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My temp dial always goes up to 9pm and stays there steady.
Hello Andrew, here's a not too steep bit of the learning curve. To check the actual running temperature, you can switch on the Trip Screen Diagnostic system. This allows you to see the temperature changing in real time in degrees Centigrade. It provides lots of other interesting stuff, but the running temperature is what most people use it for. The How To is here: https://www.the75andztclub.co.uk/for...ad.php?t=55585
Concentrate on section 7 for engine temperature.


You'll probably need to practice the button presses, but you'll quickly get the hang of it. The diesel ought to run aound 85-90C, but for various reasons, few actually do. If you find your 'normal' running temperature is closer to 75C, you should consider fitting the in-line thermostat modification. It's pretty easy to do and has benefits all round. See this How To: https://www.the75andztclub.co.uk/for...d.php?t=100594


Quote:
I did a bit of reading and tried to set the fan going by turning the ignition on and putting the demister on full blast on lo temp. Tried various combos of air con, econ, engine off, engine on etc. The fan doesn't move.
Here's a 3-speed radiator fan testing routine posted years ago by Jules. I think it still applies to the original 3-speed system. It may confirm the state of the motor.

https://www.the75andztclub.co.uk/for...ight=jules+fan
You could try fitting new brushes or if that isn't possible, a popular fix is to replace the fan conpletely with a second hand 2-speed system or a third party fan kit (Jules sells one).



Hope this helps.
TC
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Old 9th March 2021, 11:34   #13
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Originally Posted by T-Cut View Post
Hello Andrew, here's a not too steep bit of the learning curve. To check the actual running temperature, you can switch on the Trip Screen Diagnostic system. This allows you to see the temperature changing in real time in degrees Centigrade. It provides lots of other interesting stuff, but the running temperature is what most people use it for. The How To is here: https://www.the75andztclub.co.uk/for...ad.php?t=55585
Concentrate on section 7 for engine temperature.


You'll probably need to practice the button presses, but you'll quickly get the hang of it. The diesel ought to run aound 85-90C, but for various reasons, few actually do. If you find your 'normal' running temperature is closer to 75C, you should consider fitting the in-line thermostat modification. It's pretty easy to do and has benefits all round. See this How To: https://www.the75andztclub.co.uk/for...d.php?t=100594


Here's a 3-speed radiator fan testing routine posted years ago by Jules. I think it still applies to the original 3-speed system. It may confirm the state of the motor.

https://www.the75andztclub.co.uk/for...ight=jules+fan
You could try fitting new brushes or if that isn't possible, a popular fix is to replace the fan conpletely with a second hand 2-speed system or a third party fan kit (Jules sells one).



Hope this helps.
TC
Thanks for the post, T-Cut. Very informative! I was planning on looking into the trip screen thing later on so thank you for providing the link with info. All I need now is an excuse to go out tonight. I suspect food shopping will raise less eyebrows with the wife than me telling her I'm going out to tinker with the Rover yet again

I began reading that guide from Jules late last night but my brain was too fried to take it in properly. I plan on reading it properly soon.
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Old 9th March 2021, 17:50   #14
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T-Cut,

Thanks for your detailed guide on the diagnostic access. I managed to get the screen I wanted on the second attempt. Much like my drivers licence.

Took the car for a 45 minute drive on a variety of roads using all styles of driving...apart from getaway driving and drifting. I'm averaging around 83-85 so not too bad.

A nifty on board feature!
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Old 9th March 2021, 21:44   #15
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Hi Colvert,

I'm not sure I know what you mean but with the air con switched on, I looked through the grille and the radiator fan was not turning. My air con seems to work okay when driving. Less so when stationary. Again I find this all confusing but I guess the air flow generated while driving explains this?
With the air-con switched on and the engine ticking over the fan should regularly switch off and on.

If it doesn't then probably the brush gear is worn.


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Old 10th March 2021, 08:02   #16
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With the air-con switched on and the engine ticking over the fan should regularly switch off and on.
Errr ... if yours is doing that Jon then I am afraid that you have a fault.

Andrew; with the ignition on or engine running, press the windscreen demist button. Your air conditioning should now activate (identified by the compressor engaging) and your radiator fan should run continuously.

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Old 10th March 2021, 09:13   #17
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Thanks for your input again, Simon. From doing some reading of the forum before raising my thread, I was aware there might be some different opinions on when the fan is meant to kick in/how it operates etc. I have established though that mine neither kicks in nor operates Perhaps the high speed still works but I need to read the guide on testing that out.

Andrew
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Old 10th March 2021, 11:44   #18
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I have established though that mine neither kicks in nor operates ... Perhaps the high speed still works but I need to read the guide on testing that out.
Hi Andrew,

Here's a simplified guide to testing the 3 speed fan.
  1. To test the low speed, press the windscreen demist button with the ignition on (or engine running). The fan should run continuously.
  2. To test the medium speed you will need to identify the trinary switch connector and join together terminals 2 (black wire) and 3 (yellow/grey).
  3. The high speed cannot easily be tested.

Things to bear in mind:
  • As Arctic says, with a failed low speed it's extremely likely that the medium speed won't work either. This is because they share an earth brush and it is this which wears down first. Even if you're lucky and the medium speed is still working, it will not enable the air con. to work efficiently at low road speeds.
  • With a diesel there is no point in relying on the high speed. It will never be triggered since it requires a coolant temperature of 112 C and is not used by the air conditioning at all.
  • Air conditioning isn't only for hot summer temperatures. Its dehumidifying effect is useful all the year around to stop the windows misting and making the interior a more pleasant place to be, and you get plenty of moisture in Scotland!

The fan systems are quite complex and differ depending upon the engine type. I have a 3 speed system like yours and I renewed the motor brushes a long time ago now and it's been totally reliable. It was then that I investigated the various circuits and I have a file full of technical information on them! The diesel is unusual in that it uses PWM decoding electronics to drive the relays and that in itself can be a source of trouble.

If you're technically minded you can restore your fan motor to working order for about £20 by buying a set of brushes from Engineering Carbon Products Ltd. Arctic has posted one of his excellent pictorial guides to the work involved.

Simon
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Last edited by SD1too; 10th March 2021 at 11:50..
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Old 10th March 2021, 13:16   #19
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Hi Andrew,

Here's a simplified guide to testing the 3 speed fan.
  1. To test the low speed, press the windscreen demist button with the ignition on (or engine running). The fan should run continuously.
  2. To test the medium speed you will need to identify the trinary switch connector and join together terminals 2 (black wire) and 3 (yellow/grey).
  3. The high speed cannot easily be tested.

Things to bear in mind:
  • As Arctic says, with a failed low speed it's extremely likely that the medium speed won't work either. This is because they share an earth brush and it is this which wears down first. Even if you're lucky and the medium speed is still working, it will not enable the air con. to work efficiently at low road speeds.
  • With a diesel there is no point in relying on the high speed. It will never be triggered since it requires a coolant temperature of 112 C and is not used by the air conditioning at all.
  • Air conditioning isn't only for hot summer temperatures. Its dehumidifying effect is useful all the year around to stop the windows misting and making the interior a more pleasant place to be, and you get plenty of moisture in Scotland!

The fan systems are quite complex and differ depending upon the engine type. I have a 3 speed system like yours and I renewed the motor brushes a long time ago now and it's been totally reliable. It was then that I investigated the various circuits and I have a file full of technical information on them! The diesel is unusual in that it uses PWM decoding electronics to drive the relays and that in itself can be a source of trouble.

If you're technically minded you can restore your fan motor to working order for about £20 by buying a set of brushes from Engineering Carbon Products Ltd. Arctic has posted one of his excellent pictorial guides to the work involved.

Simon
Thanks, Simon! Judging by the temperature test I did yesterday with the onboard diagnostics I understand why the high fan will probably never be needed unless I have a cooling catastrophe.

I don't know if I would describe myself as technically minded I have fixed a lot of things on my cars from mechanical stuff to the silly stuff like leaking boots but my achilles heel has always been electrical issues and faults. I simply do not understand that side of things and so far have made no effort to understand them. Silly really as cars are full of electrics.
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Old 10th March 2021, 17:56   #20
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I have fixed a lot of things on my cars from mechanical stuff ... but my achilles heel has always been electrical issues and faults.
The only specialist skill you'll need for brush replacement is using a soldering iron! Otherwise it's a mechanical job.

Simon
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