Cooling fan won't stop

Danish75Driver · 12th August 2022, 07:30

I stopped the V6 engine of my 75 after a short ride and the cooler fan kept running, which is normal when the engine block is to be cooled.
However, it kept running and I had to disconnect the battery.
The day before, I also had the same problem, but after restarting the engine a couple of times, the Cooler fan stopped. But then I could not restart the car before the engine block was completely cold.
Now it's in the garage waiting for my investigation.
Any hints before i Proceed?
Tnks
Hans in Denmark

vitesse · 12th August 2022, 08:16

I'm guessing one of the relays in the control box has fused. Unfortunately the control box is well hidden and not easily accessible, and if a garage is going to do the work be prepared for a large bill of at least three hours work.

Have you tried activating the fan using the freeware programme Toaf? An essential tool for us outside of the UK.

If you plan on doing the work yourself and would like to borrow a set of relays I've got at least one spare control unit in the garage. Can you see a resistor at the 2 o'clock position when looking in through the grille?

Regards

ps The non-starting until the engine is cold is unusual, defective temperature sensor (?). Could you run the test 7.0 described here and tell us what the readings are 1. when cold 2. normal driving

dave lincs · 12th August 2022, 08:19

Hi Hans

As Vitesse has said it will be a relay in the control box that has failed

Dave

Danish75Driver · 12th August 2022, 08:25

No I do not know of any free software. Any link to the stuff to read and understand. I do have an electronic background so why not try?

Quote:

Originally Posted by vitesse

I'm guessing one of the relays in the control box has fused. Unfortunately the control box is well hidden and not easily accessible, and if a garage is going to do the work be prepared for a large bill of at least three hours work.

Have you tried activating the fan using the freeware programme Toaf? An essential tool for us outside of the UK.

If you plan on doing the work yourself and would like to borrow a set of relays I've got at least one spare control unit in the garage. Can you see a resistor at the 2 o'clock position when looking in through the grille?

Regards

ps The non-starting until the engine is cold is unusual, defective temperature sensor (?). Could you run the test 7.0 described here and tell us what the readings are 1. when cold 2. normal driving

vitesse · 12th August 2022, 08:40

Your wish ... https://toaf.roverki.eu/index.php/en/

Lot's of us here use Toaf, we even have a nationwide list of Toaf users which I try and update/list on our local FB group (https://www.facebook.com/groups/1800705170206717) quite a few Norwegians but can't remember any Danes.

Regards

ps. Forgot to give you a link to the internal OBD test: https://www.the75andztclub.co.uk/for...ad.php?t=55585 Test 7.0

Danish75Driver · 12th August 2022, 12:38

Before turning into advanced solutions with app's SW and putting my Rover 75 to pieces, I would like to know a few simple things:

There must be a sensor, sensoring the temperature of the solvent in the cooling system. Where do I find that sensor and if it's a sensor just grounding to the chassis at a certain temperature, is it a NO (normally open) or NC (Normally closed switch)?
I also am aware of the fact, that the cooling fan is starting once I initiate the aircondition. Again, there must be a sensor that is activating the cooler fan, as it is running, as soon as I turn on the aircondition.
My experience is, that most problems are initiated by simpel units failing. Even a fuse can be tired from handling current through years and then it blows. and the reason is not always, that something is using too much current.
So please gentlemen. tell me some simple things to test, before I go into advanced solutions :-)

I stopped the V6 engine of my 75 after a short ride and the cooler fan kept running, which is normal when the engine block is to be cooled.
However, it kept running and I had to disconnect the battery.
The day before, I also had the same problem, but after restarting the engine a couple of times, the Cooler fan stopped. But then I could not restart the car before the engine block was completely cold.
Now it's in the garage waiting for my investigation.
Any hints before i Proceed?
Tnks
Hans in Denmark

vitesse · 12th August 2022, 13:14

Think I've already supplied most of the information you require. Run the OBD test 7.0 and you'll get the answer of the coolant temperature and will be able to determine whether the sensor is operating correctly.

The ACC and cooling fan will run irrespective of coolant temperature whenever ACC is on.

The sensor is located in the V of the engine beside the thermostat.

And a thanks to respondents is most appreciated.

Regards

Danish75Driver · 12th August 2022, 14:24

Of course I'm very happy by the help I get, so thank you.

I was just wondering, if I may stand with a very simple problem and it is of course my fault to be disappointed by the complex answer.

The car has been left in my garage for so long, that after cleaning all contacts and connectors, I'm now recovering the battery and then I shall try the diagnostic tool, build into the car

I shall keep you informed of the proceedings :-)

Happy weekend
Hans

Danish75Driver · 18th August 2022, 06:20

Due to intense help from Mike Kelland, I have now succeeded in repairing my Connoisseur. A mouse had disconnected the sensor on the motorblock from the computer :-) By removing the battery box I could slip my hand into the area of tubes and wires under the intake manifold and draw out the YSB107380 connector. I made a new heat resistant wire, that I could solder to connect to the lucky rest of wire sticking out and wupti: The Connoisseur was fit again.

Happy me, that I'm a part of this forum and now also a part of the Nordic Facebook team. Thanks to Mike and all others adding help and comments

Hans Frost
Denmark

12th August 2022, 07:30	#1
Danish75Driver Newbie Rover 75 Join Date: Jan 2022 Location: Copenhagen Posts: 5 Thanks: 0 Thanked 8 Times in 2 Posts	Cooling fan won't stop I stopped the V6 engine of my 75 after a short ride and the cooler fan kept running, which is normal when the engine block is to be cooled. However, it kept running and I had to disconnect the battery. The day before, I also had the same problem, but after restarting the engine a couple of times, the Cooler fan stopped. But then I could not restart the car before the engine block was completely cold. Now it's in the garage waiting for my investigation. Any hints before i Proceed? Tnks Hans in Denmark

12th August 2022, 08:16	#2
vitesse I really should get out more....... Rover 75 Saloon Join Date: Jul 2011 Location: Gävle Posts: 2,531 Thanks: 395 Thanked 823 Times in 652 Posts	I'm guessing one of the relays in the control box has fused. Unfortunately the control box is well hidden and not easily accessible, and if a garage is going to do the work be prepared for a large bill of at least three hours work. Have you tried activating the fan using the freeware programme Toaf? An essential tool for us outside of the UK. If you plan on doing the work yourself and would like to borrow a set of relays I've got at least one spare control unit in the garage. Can you see a resistor at the 2 o'clock position when looking in through the grille? Regards ps The non-starting until the engine is cold is unusual, defective temperature sensor (?). Could you run the test 7.0 described here and tell us what the readings are 1. when cold 2. normal driving Last edited by vitesse; 12th August 2022 at 08:20..

12th August 2022, 08:40	#5
vitesse I really should get out more....... Rover 75 Saloon Join Date: Jul 2011 Location: Gävle Posts: 2,531 Thanks: 395 Thanked 823 Times in 652 Posts	Your wish ... https://toaf.roverki.eu/index.php/en/ Lot's of us here use Toaf, we even have a nationwide list of Toaf users which I try and update/list on our local FB group (https://www.facebook.com/groups/1800705170206717) quite a few Norwegians but can't remember any Danes. Regards ps. Forgot to give you a link to the internal OBD test: https://www.the75andztclub.co.uk/for...ad.php?t=55585 Test 7.0 Last edited by vitesse; 12th August 2022 at 08:42..

12th August 2022, 14:24	#8
Danish75Driver Newbie Rover 75 Join Date: Jan 2022 Location: Copenhagen Posts: 5 Thanks: 0 Thanked 8 Times in 2 Posts	Thank you all Of course I'm very happy by the help I get, so thank you. I was just wondering, if I may stand with a very simple problem and it is of course my fault to be disappointed by the complex answer. The car has been left in my garage for so long, that after cleaning all contacts and connectors, I'm now recovering the battery and then I shall try the diagnostic tool, build into the car I shall keep you informed of the proceedings :-) Happy weekend Hans

18th August 2022, 06:20	#9
Danish75Driver Newbie Rover 75 Join Date: Jan 2022 Location: Copenhagen Posts: 5 Thanks: 0 Thanked 8 Times in 2 Posts	Final Due to intense help from Mike Kelland, I have now succeeded in repairing my Connoisseur. A mouse had disconnected the sensor on the motorblock from the computer :-) By removing the battery box I could slip my hand into the area of tubes and wires under the intake manifold and draw out the YSB107380 connector. I made a new heat resistant wire, that I could solder to connect to the lucky rest of wire sticking out and wupti: The Connoisseur was fit again. Happy me, that I'm a part of this forum and now also a part of the Nordic Facebook team. Thanks to Mike and all others adding help and comments Hans Frost Denmark

12th August 2022, 08:19	#3
dave lincs Posted a thing or two Rover 75 Saloon Join Date: Mar 2014 Location: Louth Posts: 1,412 Thanks: 380 Thanked 986 Times in 476 Posts	Hi Hans As Vitesse has said it will be a relay in the control box that has failed Dave

12th August 2022, 12:38	#6
Danish75Driver Newbie Rover 75 Join Date: Jan 2022 Location: Copenhagen Posts: 5 Thanks: 0 Thanked 8 Times in 2 Posts	Before turning into advanced solutions with app's SW and putting my Rover 75 to pieces, I would like to know a few simple things: There must be a sensor, sensoring the temperature of the solvent in the cooling system. Where do I find that sensor and if it's a sensor just grounding to the chassis at a certain temperature, is it a NO (normally open) or NC (Normally closed switch)? I also am aware of the fact, that the cooling fan is starting once I initiate the aircondition. Again, there must be a sensor that is activating the cooler fan, as it is running, as soon as I turn on the aircondition. My experience is, that most problems are initiated by simpel units failing. Even a fuse can be tired from handling current through years and then it blows. and the reason is not always, that something is using too much current. So please gentlemen. tell me some simple things to test, before I go into advanced solutions :-) I stopped the V6 engine of my 75 after a short ride and the cooler fan kept running, which is normal when the engine block is to be cooled. However, it kept running and I had to disconnect the battery. The day before, I also had the same problem, but after restarting the engine a couple of times, the Cooler fan stopped. But then I could not restart the car before the engine block was completely cold. Now it's in the garage waiting for my investigation. Any hints before i Proceed? Tnks Hans in Denmark

12th August 2022, 13:14	#7
vitesse I really should get out more....... Rover 75 Saloon Join Date: Jul 2011 Location: Gävle Posts: 2,531 Thanks: 395 Thanked 823 Times in 652 Posts	Think I've already supplied most of the information you require. Run the OBD test 7.0 and you'll get the answer of the coolant temperature and will be able to determine whether the sensor is operating correctly. The ACC and cooling fan will run irrespective of coolant temperature whenever ACC is on. The sensor is located in the V of the engine beside the thermostat. And a thanks to respondents is most appreciated. Regards