KV6 Cold Start Temp of 131c !

MikeHurley · 22nd June 2017, 07:02

It's been suggested that temperature sensor or its wiring being worn would deliver a temp of 131c at a cold start and fan going into speed 3 straight away.

Has anyone else had this experience of this before, and was it simply a case of swapping out the temp sensor?

Would the engine management system affect other aspects of the engine running if it sees a very high temp like this one at 131c?

Views from technically experienced members especially welcome.

Mike

Sent from my Nexus 5 using Tapatalk

MikeHurley · 22nd June 2017, 07:04

Photo attached now

T-Cut · 22nd June 2017, 08:03

The output from the coolant temperature sensor is used by the main ECU to control several aspects of engine management, including the fuelling and the cooling system. Clearly, the cold start temperature indicated is a fault, which the ECU is responding to by tripping on the emergency high speed fan. The simplest explanation is the head sensor is faulty, so replacing it is the logical first step. You might have a T4 check done first if you have access one.

TC

MikeHurley · 22nd June 2017, 08:49

Thanks TCut, I suspected as much. I have a spare Temp Sensor from my previous KV6 in my garage as I understand they are now a scarce commodity.

The car is in SW London but I am based in SE London, so if anyone knows of a an MG/Rover garage in that area with a T4 please let me know.

T-Cut · 22nd June 2017, 08:57

Quote:

Originally Posted by MikeHurley

I understand they are now a scarce commodity.

Nar, plenty around:

Rimmer - https://www.rimmerbros.co.uk/Item--i-MEK000030

eBay - https://www.ebay.co.uk/sch/i.html?_f...ensor&_sacat=0

A T4 check isn't essential at this stage. Things will likely be normal with a new sensor.

TC

milford man · 22nd June 2017, 09:38

Quote:

Originally Posted by MikeHurley

Thanks TCut, I suspected as much. I have a spare Temp Sensor from my previous KV6 in my garage as I understand they are now a scarce commodity.

The car is in SW London but I am based in SE London, so if anyone knows of a an MG/Rover garage in that area with a T4 please let me know.

I would just plug a new one in without fitting it for a test. If it reads something like it should on the dash you can then swap it out.

Regards John

SD1too · 22nd June 2017, 10:54

Quote:

Originally Posted by MikeHurley

I have a spare Temp Sensor from my previous KV6 in my garage ... The car is in SW London but I am based in SE London ..

Mike,

It's safe to drive the car to your home. Take it, and your spare sensor to the garage you normally use.

Simon

T-Cut · 22nd June 2017, 14:57

Quote:

Originally Posted by milford man

I would just plug a new one in without fitting it for a test. If it reads something like it should on the dash you can then swap it out.

I don't think that would work. The two wires aren't 12v and earth. One's a 5v or 6v reference voltage as I recall. The the sensor is earthed via the thead into the head.

TC

milford man · 22nd June 2017, 17:06

Quote:

Originally Posted by T-Cut

I don't think that would work. The two wires aren't 12v and earth. One's a 5v or 6v reference voltage as I recall. The the sensor is earthed via the thead into the head.

TC

AFAIK it doesn't need an earth. Its basically a thermistor which needs two connections. Even so it would be easy to get it to make contact with the engine if an earth was needed. Easier than swapping it only to find the old one wasn't faulty.

Regards John

T-Cut · 22nd June 2017, 17:21

Quote:

Originally Posted by milford man

- - - - it would be easy to get it to make contact with the engine if an earth was needed. Easier than swapping it only to find the old one wasn't faulty.

Yes he could try that. I attempted to test a sensor off the car and got nowhere, but I can't remember how I wired it up. Obviously it was wrong.

TC

EDIT: Looking at the sensor system diagram in RAVE, it seems one lead gets the 5v reference voltage and the other is earth.

22nd June 2017, 07:02	#1
MikeHurley Gets stuck in Rover 75 Saloon 2.5 V6 Join Date: Sep 2007 Location: London Posts: 659 Thanks: 129 Thanked 26 Times in 24 Posts	KV6 Cold Start Temp of 131c ! It's been suggested that temperature sensor or its wiring being worn would deliver a temp of 131c at a cold start and fan going into speed 3 straight away. Has anyone else had this experience of this before, and was it simply a case of swapping out the temp sensor? Would the engine management system affect other aspects of the engine running if it sees a very high temp like this one at 131c? Views from technically experienced members especially welcome. Mike Sent from my Nexus 5 using Tapatalk __________________ To do list: Aux Drive Belt ....... Sept 2017 Kaiser Alumium Stat Housing ....Jan 2017 Rear o/s wheel bearing set changed.....Aug 2014 Cam & Aux Belts...May 2014 Tazu Inner tie rod ends...May 2014 Need Timing Belts changed...done April 2014 Front Shocks and Strut Bearings ....done Mar 2014 Polybushes to Wishbone Arms.....done Mar 2014 Handbrake compensator changed...done Oct 2013 Exhaust Back Box a.......done 16/8/13 Quality Front Drop Links...done 16/8/13 Rear Springs ..done 16/8/13

22nd June 2017, 07:04	#2
MikeHurley Gets stuck in Rover 75 Saloon 2.5 V6 Join Date: Sep 2007 Location: London Posts: 659 Thanks: 129 Thanked 26 Times in 24 Posts	Photo attached now __________________ To do list: Aux Drive Belt ....... Sept 2017 Kaiser Alumium Stat Housing ....Jan 2017 Rear o/s wheel bearing set changed.....Aug 2014 Cam & Aux Belts...May 2014 Tazu Inner tie rod ends...May 2014 Need Timing Belts changed...done April 2014 Front Shocks and Strut Bearings ....done Mar 2014 Polybushes to Wishbone Arms.....done Mar 2014 Handbrake compensator changed...done Oct 2013 Exhaust Back Box a.......done 16/8/13 Quality Front Drop Links...done 16/8/13 Rear Springs ..done 16/8/13

22nd June 2017, 08:49	#4
MikeHurley Gets stuck in Rover 75 Saloon 2.5 V6 Join Date: Sep 2007 Location: London Posts: 659 Thanks: 129 Thanked 26 Times in 24 Posts	Thanks TCut, I suspected as much. I have a spare Temp Sensor from my previous KV6 in my garage as I understand they are now a scarce commodity. The car is in SW London but I am based in SE London, so if anyone knows of a an MG/Rover garage in that area with a T4 please let me know. __________________ To do list: Aux Drive Belt ....... Sept 2017 Kaiser Alumium Stat Housing ....Jan 2017 Rear o/s wheel bearing set changed.....Aug 2014 Cam & Aux Belts...May 2014 Tazu Inner tie rod ends...May 2014 Need Timing Belts changed...done April 2014 Front Shocks and Strut Bearings ....done Mar 2014 Polybushes to Wishbone Arms.....done Mar 2014 Handbrake compensator changed...done Oct 2013 Exhaust Back Box a.......done 16/8/13 Quality Front Drop Links...done 16/8/13 Rear Springs ..done 16/8/13

22nd June 2017, 08:03	#3
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	The output from the coolant temperature sensor is used by the main ECU to control several aspects of engine management, including the fuelling and the cooling system. Clearly, the cold start temperature indicated is a fault, which the ECU is responding to by tripping on the emergency high speed fan. The simplest explanation is the head sensor is faulty, so replacing it is the logical first step. You might have a T4 check done first if you have access one. TC