Fan sensor switch
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Fan sensor switch
Does anyone know the test values or the temp it swithes for the fan sensor switch which is screwed in to the head below the inlet manifold as mine reached 98deg and still did not come on .unplug it and the fans work.
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Grahame at work
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Re: Fan sensor switch
hi stevedon
In my last Bongo I reckoned that the ECU operated the fans when the sensor was just below 100C - so you probably were just under the switching point.
how were you measuring the temperature?
regrads Grahame
In my last Bongo I reckoned that the ECU operated the fans when the sensor was just below 100C - so you probably were just under the switching point.
how were you measuring the temperature?
regrads Grahame
Joanie2 has had a sex change and is remaned Bert
Re: Fan sensor switch
i am using a tm2 backed up by a laser thermometer
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Grahame at work
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- Joined: Fri Sep 30, 2005 12:43 pm
- Location: Aberdeen
Re: Fan sensor switch
Hi,
If you are using the TM2 fixed on to the head somewhere like most folk you are probably measuring several degrees different to the coolant temperature - either higher or lower depending on exactly where the TM2 sensor is.
As you said the sensor that the ECU uses for coolant temperature is below the manifold - about 1/3rd the way down the block and there it will be cooler than the coolant running along the head to the outlet. So the ECU needs to see about 98C in the block before it will turn on the fans. That will mean a coolant temperature of just over 100 as it leaves the head on its way to the radiator / bypass. I would expect a TM2 to be reading higher than 98C before the fans turn on.
This is of course my own assessment of how things go - others may well dispute my guess work.
If you can get at it your laser may give a good reading from the thermostat housing, I had a thermocouple fixed to my old Bongo's thermostat housing and got fairly good readings of how it performed - trying to balance at around 90C. And then a look at the head casting around the coolant outlet at the bypass which is quite thin - so you may be able to get a reasonable readings of inlet and outlet temperatures of the coolant. I'd be interested in that if you can manage it.
regards Grahame
If you are using the TM2 fixed on to the head somewhere like most folk you are probably measuring several degrees different to the coolant temperature - either higher or lower depending on exactly where the TM2 sensor is.
As you said the sensor that the ECU uses for coolant temperature is below the manifold - about 1/3rd the way down the block and there it will be cooler than the coolant running along the head to the outlet. So the ECU needs to see about 98C in the block before it will turn on the fans. That will mean a coolant temperature of just over 100 as it leaves the head on its way to the radiator / bypass. I would expect a TM2 to be reading higher than 98C before the fans turn on.
This is of course my own assessment of how things go - others may well dispute my guess work.
If you can get at it your laser may give a good reading from the thermostat housing, I had a thermocouple fixed to my old Bongo's thermostat housing and got fairly good readings of how it performed - trying to balance at around 90C. And then a look at the head casting around the coolant outlet at the bypass which is quite thin - so you may be able to get a reasonable readings of inlet and outlet temperatures of the coolant. I'd be interested in that if you can manage it.
regards Grahame
Joanie2 has had a sex change and is remaned Bert
Re: Fan sensor switch
i have the sensor located under the 12mm bolt at the front of the head on the drivers side, just by the temp sender.
It must be a good place as at an indicated 100deg the fans come on,which is the specified temp i think
It must be a good place as at an indicated 100deg the fans come on,which is the specified temp i think