KV6 coolant temp sensor location

[Dominic22]

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.

[T-Cut]

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?

[Dominic22]

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.

[T-Cut]

Originally Posted by Dominic22

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

[Dominic22]

Originally Posted by T-Cut

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

[SD1too]

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.

Originally Posted by Dominic22

... 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

[T-Cut]

Originally Posted by Dominic22

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

[Kampo]

Originally Posted by T-Cut

Does the radiator fan start when you start the engine?
Does the temperature gauge stay in its ignition-off position?

TC

hi T cut i know this is now quite an old post but i suffer from both of these symptoms. i had posted here a while back about the fact the car had been static for some time. at the time i was told to check the cables in the v leading to the coolant sensor in case any rodents had eaten them. i m yet to achieve this i m hoping i ll be able to in next few weeks as i m battling taking off the inlet manifold with work duties etc however i want to ask can it be coincidental that i also have no revs at the same time? i m hoping the coolant temp staying at cold and the fan kicking in immediately after i start the engine is isolated to the engine revs not showing- i m really hoping it s not ecu as i never found the plenum to have got any water and i do clean the plug hole fairly regularly. do you have any idea other than replacing coolant temp sensor what else i could be faced with and how else to tackle the rev meter issue? i have done instrument cluster check and it all checks out good

[SD1too]

Originally Posted by Kampo

... i m hoping the coolant temp staying at cold and the fan kicking in immediately after i start the engine is isolated to the engine revs not showing ...

Hi Marios,

Normally the gauge reading full cold with the radiator fan running means a problem with the coolant temperature sensor signal reaching the ECU. You're saying that also your rev. counter isn't working even though the engine runs normally?

Both the coolant temperature and rev. counter signals are transmitted from the ECM to the instrument pack on the CAN bus. Do you have any other apparently unrelated faults which might confirm this?

Simon