CDTI rad fan not switching off - Page 2

SD1too · 25th August 2017, 07:08

Quote:

Originally Posted by cb750chris

... he didn't have the aircon on, did he? As that will put the fan on until the ignition turns off ...

The evidence in Dave's first post rules that out Chris. He says that the fan continued to run for more than 30 minutes

after the engine was stopped.

Quote:

... so the fan could be doing what it should (although 30 mins is a bit long, I would have expected the engine to have cooled down sufficient in that time)..

MGR states that the 1.8 fan can run for five minutes after the engine is turned off, the KV6 for ten minutes but no data at all is given for the diesel so it may not even have this feature. Have any diesel owners ever noticed thir fan running on when the engine is stopped I wonder? I doubt it, other than those with a fault condition.

Simon

cb750chris · 25th August 2017, 09:44

Hi Simon,
I also suspect it is nothing to do with the air con, but just wanted confirmation (the post says engine stopped, but not ignition off - I didn't want to make a silly assumption)

As for the fan running on in an overheat condition - I think I have had that in my Diesel when the inline stat failed closed (sure I had turned the ignition off), but didn't time how long it ran on for.

Just want to make sure that the owner doesn't end up having his car prodded and probed far more than required for a fault that isn't there.

But I have had a car do something similar, but then it corrected itself with a battery off reset - Which Dave suggests has happened already (But I was playing around with ECUs at the time, so I probably upset the car in the first place)

Chris

T-Cut · 25th August 2017, 10:12

With the ignition off, I assume the fan control system/PCB is not active, yet the fan is running. On the logical face of it, the earth side is connected to ground 'permanently'. Hence my proposal to check the relays.

TC

SD1too · 25th August 2017, 10:43

Quote:

Originally Posted by T-Cut

With the ignition off, I assume the fan control system/PCB is not active ...

It would have to be powered, on the petrol engines at least, in order to achieve the five or ten minute fan period once the engine is stopped, ignition key removed and car locked. In addition to this, remember that the ECUs remain active for some considerable time irrespective of whether the ignition is turned off or on.

Simon

T-Cut · 25th August 2017, 13:16

The fan ran for at least half an hour before the AA man disconnected the battery. When the battery was reconnected (some time later presumably), the fan started again. In effect, there's a direct short to earth from the motor. I can only envision a stuck relay to explain it.

TC

SD1too · 25th August 2017, 16:50

Quote:

Originally Posted by T-Cut

When the battery was reconnected (some time later presumably), the fan started again.

'Presumably'? We just don't know do we. It could have been reconnected straight away.

I'm sure that Chris will sort it out and report back.

Simon

Arctic · 25th August 2017, 22:05

I Have seen this a couple of times and both had chaffed or perished wires touching the body, in the passenger wheel arch liner, so all wires will have to be checked, I am sure Chris will find the problem and report back to us with his findings

COLVERT · 30th August 2017, 20:04

Quote:

Originally Posted by french dave

Hello
The rad fan on my fathers 2004 CDTI 110k miles has a problem.
Today after a 5 mile drive, he turned off the engine and the fan stuck on

He got to his local garage who disconnected the battery and reconnected it to stop it.
Then drove 4 miles home, and it stayed on. For more than 30 minutes
He has AA home start so called them, who did the same and said rad fan control unit was at fault
However i think that the problem could be a stuck relay.
Am I right
My father will have to get the work done, as he is 82, and I live in France whilst he is in southampton.
Any thoughts please

Just reading your post again. If the relay is stuck on the fan will run until the battery is totally discharged.

You say the garage disconnected the battery then reconnected it and the fan stopped.

Your father drove home and the fan ran for more than 30 minutes. Did it stop by itself or did it flatten the battery ?

As this happened a little while ago have you had any luck in curing the fault yet ??

I know this is worrying with someone of your fathers age. ( I'm 80 myself any second now. Lol. )

25th August 2017, 09:44	#12
cb750chris Trader Rover 75 Tourer Join Date: Apr 2011 Location: Portsmouth Posts: 849 Thanks: 201 Thanked 292 Times in 200 Posts	Hi Simon, I also suspect it is nothing to do with the air con, but just wanted confirmation (the post says engine stopped, but not ignition off - I didn't want to make a silly assumption) As for the fan running on in an overheat condition - I think I have had that in my Diesel when the inline stat failed closed (sure I had turned the ignition off), but didn't time how long it ran on for. Just want to make sure that the owner doesn't end up having his car prodded and probed far more than required for a fault that isn't there. But I have had a car do something similar, but then it corrected itself with a battery off reset - Which Dave suggests has happened already (But I was playing around with ECUs at the time, so I probably upset the car in the first place) Chris __________________ Now offering T4 services in the Fareham area Replacement keys programmed / supplied / cut Diesel 135 upgrade available IPK virginisation and T4 matching available Sorry, due to a big change in home circumstances, I am unable to do any large jobs at present, but can still offer evening time diagnostics.

25th August 2017, 22:05	#17
Arctic Give to Learn Freelander 2 Join Date: Aug 2010 Location: West Midlands Posts: 18,699 Thanks: 1,155 Thanked 6,407 Times in 3,874 Posts	I Have seen this a couple of times and both had chaffed or perished wires touching the body, in the passenger wheel arch liner, so all wires will have to be checked, I am sure Chris will find the problem and report back to us with his findings __________________ Arctic Givology Learn to Give Everything is Achievable ad altiora tendo. Check out our Nano meet dates http://www.midlandsnanomeets.co.uk/ http://www.the75andztclub.co.uk/index.php?thepage=howto " You do the work , we supply the expertise "

25th August 2017, 10:12	#13
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,752 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	With the ignition off, I assume the fan control system/PCB is not active, yet the fan is running. On the logical face of it, the earth side is connected to ground 'permanently'. Hence my proposal to check the relays. TC

25th August 2017, 13:16	#15
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,752 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	The fan ran for at least half an hour before the AA man disconnected the battery. When the battery was reconnected (some time later presumably), the fan started again. In effect, there's a direct short to earth from the motor. I can only envision a stuck relay to explain it. TC