Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > Technical Help Forum
Register FAQ Image Gallery Members List Calendar Search Today's Posts Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 25th May 2017, 12:17   #1
Dominic22
Posted a thing or two
 
Rover 75 V8 Plus Others

Join Date: Jul 2011
Location: Swadlincote
Posts: 1,604
Thanks: 18
Thanked 163 Times in 81 Posts
Default KV6 coolant temp sensor location

I am sorting a cooling issue on a V6 that I have recently got. Just spoke to the previous owner and the coolant temperature sensor was replaced. When I have looked they have plugged it in next to the coolant pipes on the engine block but not connected the other side.....

I cant quite see where it plugs in does anyone have a diagram or know where it goes. I have removed enough to get it but don't want to remove the manifold just to plug it in

This is the sensor I mean https://www.dmgrs.co.uk/products/oem...45-75-zr-zs-zt it is plugged into the sensor but not they did not connect the harness.
Dominic22 is offline   Reply With Quote
Old 25th May 2017, 12:32   #2
T-Cut
This is my second home
 
Rover75 and Mreg Corsa.

Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,715
Thanks: 341
Thanked 3,635 Times in 2,914 Posts
Default

Does the fan run when you start the engine? If the sensor isn't sending a signal to the ECU, it will trip on the emergency cooling program.

The sensor is located on top of the engine, near the thermostat housing (between the 'V').

What do you mean by 'plugged in' next to the pipes, but 'not connected' the other side'? Is there not a wiring harness plugged into the end of the sensor?
T-Cut is offline   Reply With Quote
Old 25th May 2017, 12:52   #3
Dominic22
Posted a thing or two
 
Rover 75 V8 Plus Others

Join Date: Jul 2011
Location: Swadlincote
Posts: 1,604
Thanks: 18
Thanked 163 Times in 81 Posts
Default

Thanks. It is connected to the sensor i.e in the V next to the thermostat but I assume when changed they forgot to connect the other end of the harness


As this picture in post 2 https://the75andztclub.co.uk/forum/s...ad.php?t=37359 it is plugged in as here but the other end of the harness is not connected.

Last edited by Dominic22; 25th May 2017 at 12:58..
Dominic22 is offline   Reply With Quote
Old 25th May 2017, 13:18   #4
T-Cut
This is my second home
 
Rover75 and Mreg Corsa.

Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,715
Thanks: 341
Thanked 3,635 Times in 2,914 Posts
Default

Quote:
Originally Posted by Dominic22 View Post
Thanks. It is connected to the sensor i.e in the V next to the thermostat but I assume when changed they forgot to connect the other end of the harness
Does the radiator fan start when you start the engine?
Does the temperature gauge stay in its ignition-off position?

TC
T-Cut is offline   Reply With Quote
Old 25th May 2017, 13:40   #5
Dominic22
Posted a thing or two
 
Rover 75 V8 Plus Others

Join Date: Jul 2011
Location: Swadlincote
Posts: 1,604
Thanks: 18
Thanked 163 Times in 81 Posts
Default

Quote:
Originally Posted by T-Cut View Post
Does the radiator fan start when you start the engine?
Does the temperature gauge stay in its ignition-off position?

TC
No & No

All function ok other than pressure in the tank so coolant is not cycling around I have I just need to see where it plugs in as I they have changed the sensor but not plugged it in.... I cannot see a photo or haynes where the harness connects
Dominic22 is offline   Reply With Quote
Old 25th May 2017, 16:21   #6
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Middlesex
Posts: 19,086
Thanks: 1,520
Thanked 3,684 Times in 3,124 Posts
Default

Dominic,

I understand what you're asking and you're right, the wiring from the sensor connector is short and terminates just to the rear of the right-hand bank where there is another connector buried underneath the plastic inlet manifold chamber.

However, in reply to T-Cut's question you said that the temperature gauge does not remain in the full cold position when the engine is warm. Have I understood that correctly? If the gauge needle is rising towards the mid-position as the engine warms then the sensor must be connected.
Quote:
Originally Posted by Dominic22 View Post
... other than pressure in the tank so coolant is not cycling around ...
Pressure in the tank? Did you remove the expansion tank cap when the engine was stone cold? Did you hear a strong hissing sound?
Why do you believe that the coolant isn't "cycling around"? It will circulate provided that the water pump impeller hasn't dropped off its shaft!

Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.
SD1too is offline   Reply With Quote
Old 25th May 2017, 18:05   #7
T-Cut
This is my second home
 
Rover75 and Mreg Corsa.

Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,715
Thanks: 341
Thanked 3,635 Times in 2,914 Posts
Default

Quote:
Originally Posted by Dominic22 View Post
No & No
All function ok other than pressure in the tank so coolant is not cycling around- - -
It's not possible to verify coolant circulation other than by the way it controls the running temperature. There's no circulation through the header tank, so an apparent lack of flow there is meaningless I'm afraid.

From what you've said, the temperature gauge seems to be working and will provide important clues. Does the gauge sit at 'normal' (9 o'clock position) when driving? If so, the coolant is circulating. This fact is unequivocal. If there were no circulation, the gauge would hit the red line in a few minutes.

Pressurisation of the header when the engine's running is a natural consequence of the sealed coolant system getting hotter. The hotter it gets, the higher the internal pressure. The system runs quite normally up to 22psi or so using a '140' pressure cap. It's designed to do that and the cap shouldn't be touched other than for checking the fluid level when the engine is completely cold.

I honestly think your concern about the sensor harness is unfounded, unless there's another temperature related issue you've not mentioned.

TC
T-Cut is offline   Reply With Quote
Old 26th May 2017, 15:13   #8
Dominic22
Posted a thing or two
 
Rover 75 V8 Plus Others

Join Date: Jul 2011
Location: Swadlincote
Posts: 1,604
Thanks: 18
Thanked 163 Times in 81 Posts
Default

Apologies for the late reply and the hurried one now. I have uploaded a few photos of the connector I mean I will have a good look over the weekend and report back. Here is a link to the photo. I just assumed it must be plugged into something.

Maybe they have wired it differently. What led me to believe there is an issue is that I was sure that when the car was running coolant would come out the little hole top left of the tank and recirculate, is that not the case.

https://goo.gl/photos/kb36iZZkfQ4ty39Y8.

Last edited by Dominic22; 26th May 2017 at 15:18..
Dominic22 is offline   Reply With Quote
Old 26th May 2017, 16:41   #9
T-Cut
This is my second home
 
Rover75 and Mreg Corsa.

Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,715
Thanks: 341
Thanked 3,635 Times in 2,914 Posts
Default

Quote:
Originally Posted by Dominic22 View Post
What led me to believe there is an issue is that I was sure that when the car was running coolant would come out the little hole top left of the tank and recirculate, is that not the case.
The small hole you mention is of no significance in terms of coolant circulation. It's usually watched when the system is being refilled and bled. The small hose connected to the header tank neck connects to this 'bleed' hole and vents air from the heads as they fill. However, there's a much larger hole also leading from the bleed hose that's out of sight under the neck. During normal operation, the smaller hole is sealed off by the pressure cap o-rings. It may also be possible to observe a tiny flow from the other hole when the engine's running (and the cap off of course), but it's of no significance. It may even stop completely when the tank's sealed and pressurised. The header contents are basically a stagnant reserve of coolant that doesn't reach the same temperature as the engine coolant. For more details see: https://the75andztclub.co.uk/forum/s...d.php?t=245285

I'm unfamiliar with the V6 so can't comment on the plug in the photo.

Can you confirm that the temperature gauge points at 'normal' when driving?

What circumstances did you notice pressure in the header tank?

TC
T-Cut is offline   Reply With Quote
Old 16th May 2022, 21:37   #10
Kampo
Newbie
 
Rover 75

Join Date: Mar 2015
Location: london
Posts: 6
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Quote:
Originally Posted by Dominic22 View Post
Apologies for the late reply and the hurried one now. I have uploaded a few photos of the connector I mean I will have a good look over the weekend and report back. Here is a link to the photo. I just assumed it must be plugged into something.

Maybe they have wired it differently. What led me to believe there is an issue is that I was sure that when the car was running coolant would come out the little hole top left of the tank and recirculate, is that not the case.

https://goo.gl/photos/kb36iZZkfQ4ty39Y8.
i know this is an old post but this one plug next to the throttle body you have in the pic is not for the coolant temp sensor. did you ever find out?
Kampo is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 08:35.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Copyright © 2006-2022, The Rover 75 & MG ZT Owners Club Ltd