Temperature gauge & cooling fan

alanwheaton · 1st July 2018, 08:51

Has anyone ever experienced this problem. I have a 1.8 turbo petrol Connoisseur SE on an 03 plate which I have owned for about 14 months. During the last month on several occasions the temperature gauge has dropped to cold without warning. When this happens the cooling fan is on constantly and curiously the radiator expansion tank is cold. I can remove the top and there doesn't seem to be any pressure. If I turn the engine off for a couple of minutes the fan stops and on restarting the engine, the expansion tank starts to warm up and the temperature gauge returns to normal and reads dead centre. There is no logic to when this happens. I can go on a 100 mile run without any problem, but then on a short run to the local car wash, the symptoms appeared while the car was idling as it was being cleaned. I hope somebody is able to suggest what might be causing this problem.

Many thanks in anticipation of your replies, Alan

Ratty · 1st July 2018, 09:02

Could be your temperature sensor, front of engine slight right side un plug & try if not replace sensor.

T-Cut · 1st July 2018, 09:45

Nine times out of ten, this problem is caused by a bad connection to the temperature sensor. If the sensor signal is lost, the gauge drops to the 'Off' position and ECU switches on the emergency cooling strategy. This is the radiator fan at high speed. The temperature senors themselves are usually bombproof.

I'd suggest you check the condition of the wiring connector that plugs onto the sensor. This is located near the head coolant outlet. Ensure the connections are clean and tight.

TC

Brunty · 1st July 2018, 11:51

Agreed that the temperature sensor is at fault, same happened to me, new temperature sensor fitted. No more problems.

alanwheaton · 1st July 2018, 16:25

Thanks for your suggestion as to the cause of my problem. I'll check and clean the wiring of the connector that plugs onto the sensor and if that fails to resolve the problem I'll get a new temperature sensor fitted. Regards, Alan.

alanwheaton · 31st July 2018, 14:57

I had my Rover in at my local garage for them to check the connector to the temperature sensor as suggested. The connector was cleaned and the condition of the wiring checked. That was over 3 weeks ago and the problem is resolved and has not reappeared. Thanks to all who suggested this cheap fix.
Regards, Alan.

1st July 2018, 08:51	#1
alanwheaton Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Wigan Posts: 3 Thanks: 0 Thanked 4 Times in 1 Post	Temperature gauge & cooling fan Has anyone ever experienced this problem. I have a 1.8 turbo petrol Connoisseur SE on an 03 plate which I have owned for about 14 months. During the last month on several occasions the temperature gauge has dropped to cold without warning. When this happens the cooling fan is on constantly and curiously the radiator expansion tank is cold. I can remove the top and there doesn't seem to be any pressure. If I turn the engine off for a couple of minutes the fan stops and on restarting the engine, the expansion tank starts to warm up and the temperature gauge returns to normal and reads dead centre. There is no logic to when this happens. I can go on a 100 mile run without any problem, but then on a short run to the local car wash, the symptoms appeared while the car was idling as it was being cleaned. I hope somebody is able to suggest what might be causing this problem. Many thanks in anticipation of your replies, Alan

1st July 2018, 09:02	#2
Ratty I really should get out more....... MG ZTT CDTI Honda Jazz 1.4 Auto Join Date: Oct 2012 Location: Cornwall Posts: 2,166 Thanks: 1,341 Thanked 888 Times in 594 Posts	Could be your temperature sensor, front of engine slight right side un plug & try if not replace sensor. __________________ Membership Number 001426 I'll do it Drekley. Regards Allen.

1st July 2018, 09:45	#3
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	Nine times out of ten, this problem is caused by a bad connection to the temperature sensor. If the sensor signal is lost, the gauge drops to the 'Off' position and ECU switches on the emergency cooling strategy. This is the radiator fan at high speed. The temperature senors themselves are usually bombproof. I'd suggest you check the condition of the wiring connector that plugs onto the sensor. This is located near the head coolant outlet. Ensure the connections are clean and tight. TC Last edited by T-Cut; 1st July 2018 at 09:54..

31st July 2018, 14:57	#6
alanwheaton Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Wigan Posts: 3 Thanks: 0 Thanked 4 Times in 1 Post	Temperature gauge & cooling fan I had my Rover in at my local garage for them to check the connector to the temperature sensor as suggested. The connector was cleaned and the condition of the wiring checked. That was over 3 weeks ago and the problem is resolved and has not reappeared. Thanks to all who suggested this cheap fix. Regards, Alan.

1st July 2018, 11:51	#4
Brunty Loves to post Rover 75 Saloon Join Date: Mar 2017 Location: Newtown Posts: 415 Thanks: 273 Thanked 95 Times in 65 Posts	Agreed that the temperature sensor is at fault, same happened to me, new temperature sensor fitted. No more problems.

1st July 2018, 16:25	#5
alanwheaton Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Wigan Posts: 3 Thanks: 0 Thanked 4 Times in 1 Post	Thanks for your suggestion as to the cause of my problem. I'll check and clean the wiring of the connector that plugs onto the sensor and if that fails to resolve the problem I'll get a new temperature sensor fitted. Regards, Alan.