25 replies to this topic

[snoopstah]

Hi guys, Can anyone tell me (preferably with a photo) where the coolant temperature sensor is on the VXT? And how easy it is to replace? Mine seems to be playing up a little, generally fine at normal temperatures but seems a bit iffy when overly warm (jumping around quite a lot, 95 -> 75 -> 95 etc.) or overly cold (on startup yesterday it read -18 degrees for a few seconds).

[John Faulkner]

Hi guys,

Can anyone tell me (preferably with a photo) where the coolant temperature sensor is on the VXT? And how easy it is to replace?

Mine seems to be playing up a little, generally fine at normal temperatures but seems a bit iffy when overly warm (jumping around quite a lot, 95 -> 75 -> 95 etc.) or overly cold (on startup yesterday it read -18 degrees for a few seconds).

i'm pretty sure its tucked away under here somewhere. this is only from memory though, so may be wrong!

[snoopstah]

Thanks

[redvts]

i changed that sensor on mine mate because mine was playing up then went off all together, got the sensor from vauxhall changed it and its still the same, went back to vauxhall and one of their 'technicians' said theres a seperate one for the clocks, sold me another sensor but couldnt remember/tell me where it went, had a good look round the engine when ive been doing other stuff cant find where it goes, still dont know if ther is actually 2 sensors or he just made it up in his tiny little dealership brain, let me know if you get sorted mate

[starlight]

There are 2:
Sensor 1
Sensor 2

[redvts]

ah so it looks like the one we need to change is in the front, didnt check there as the vauxhall person/numpty said there wasn't any in the front, what a helmet, cheers mate

[starlight]

DOH!
They have the same part number!!

there is only one then:

Coolant Sensor Positions on Engine

From the description on the next page :
"The coolant temperature sensor is mounted in the thermostat housing and is a thermistor, whose
resistance decreases as the coolant temperature increases.
The resistance of the coolant temperature sensor is monitored by the engine control unit for use in
calculating the injection quantity and in operating the cooling fan."

DOH!
From the wiring diagram, the coolant temp gauge picks up the reading from the ECU based on this sensor

Slightly off topic, on my old Elan Turbo, there were three sensors - one for the ECU, one for the temp gauge, and one for the radiator fan...

[CraigBaker]

did you get sorted?

[redvts]

the bloke at the stealership did say that there was one for the ECU which is the one ive changed and one for the readout but still dont know where it is

[starlight]

There is definately only the one sensor (further to my previous posts ) - heres the wiring diagram for the instrument cluster

Instrument panel wiring

The Coolant temp indicator is H1.22, goes from terminal A6 with a Green/Blue wire to the Engine harness.

Engine Wiring diagram, Z20LET (Turbo)

The coolant sensor is B61 and feeds the ECU (A5) pin 38. Pin 35 is the connector to the Instrument panel with the Green/Blue wire

Edited by pjohn151, 23 July 2009 - 02:29 PM.

[MikeF]

Snoopstah, the sensor for the coolant temp on the dash is located under the drivers side front wheel arch, take the wheel arch liner out and you will see it, its a stack supplied sensor Cheers and hope the cars well Mike

[Gilgamesh]

ok instead of starting a new thread I use this... my dash temperature is jumping up and down, and sometimes it just disappears, this happened yesterday... so I guess one of the two sensors is fault (or maybe both), is it the one in engine bay or the one under the drivers side front wheel arch liner? I have ordered a opcom maybe it can tell me which one, until then I use Torque app to check the temprature.

 

[CHILL Gone DUTCH]

ok instead of starting a new thread I use this... my dash temperature is jumping up and down, and sometimes it just disappears, this happened yesterday... so I guess one of the two sensors is fault (or maybe both), is it the one in engine bay or the one under the drivers side front wheel arch liner? I have ordered a opcom maybe it can tell me which one, until then I use Torque app to check the temprature.  

This can be caused by a crack in the coolant bottle or the coolant bottle lid is not allowing system to pressurise ( try tightening a bit more) Check this first dosent cost much to check this

Edited by CHILL Gone DUTCH, 04 July 2013 - 06:46 AM.

[Gilgamesh]

ok will check it, the coolant bottle was replaced not long time ago.

[siztenboots]

check the one in the engine block , just beneath the coil pack plug , chances its the connector

[Gilgamesh]

ok, will check it, btw, seems to be the same sensor for front and rear?

 

http://www.ebay.co.u...0541937&_sop=15

 

is that the correct one?

Edited by Gilgamesh, 04 July 2013 - 12:48 PM.

[jayworth2]

Just thought i'd add this in case someone has a similair fault. My VXT had starting issues, had to give a few presses of the accelerator to help start it when cold only. Tried new plugs and was ready to change coilpack when i noticed occasionally it was stating 72 degrees C periodically on cold start up. Almost changed coolant temp sensor when i tried what siztenboots suggested about the connector and put some ACF 50 spray on the connecter and cured the fault.

[harboged]

Seems to be some confusion about the coolant sensor(s). Does the VXT have one in the front? Can't remember I saw one when I changed the rad. If there are two sensors, has it been clarified which one causes the dash gauge to go crazy?

[glitch]

no coolant sensor in the front as far as I know - should have seen it when we did my rad and Gilgamesh's rad

[siztenboots]

wiring diagram mentions 

 

Z22SE

B12 Sensor - Coolant temperature  (page 9 , ECU pintouts) , via ECU , output to INS 718 #GNBU wire

 

Z20LET

B61 Sensor - Coolant temperature (gauge)  (page 7 , ecu pinouts) , via ECU , output to INS 718 #GNBU wire