Vauxhall Cavalier 2.0 CDX 1995 - Coolant Level Sensor -how does it work

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Tue 1 May 2012 01:45
Vauxhall Cavalier 2.0 CDX 1995 - Coolant Level Sensor -how does it work - peter973

Does anyone know how the Coolant Level Sensor works ??

It is integral with the coolant expansion tank cap.
( I will post a picture later of the cap & sensor)

Recently my dasboard Coolant Low Level Warning Lamp has been coming on & I am losing some coolant. So I have been having to check my coolant regularly.

I am curious and cannot see how this sensor works.

I can't see it is pressure based, as in normal operation, when you switch on ignition (engine not started) the Low Level Warning Lamp goes out.

There are 2 electrical contacts that go to the sensor in the cap. I can't see how the sensor monitors coolant level. There's a 5 inch plastic arm which goes down from the cap into the coolant. At bottom of this arm is a float type device that can move up/down the arm 1/4 inch.

There is no obvious link between the coolant level & the sensor at top of cap & how it is monitored/triiggered.

Anyone know how this works ??

Edited by peter973 on 01/05/2012 at 01:52

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Tue 1 May 2012 09:08
Vauxhall Cavalier 2.0 CDX 1995 - Coolant Level Sensor -how does it work - elekie&a/c doctor

Within the float is a magnet.As the coolant level rises or falls this magnet operates a reed switch (open/closed) which in turn signals the warning light circuit.hth

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Wed 2 May 2012 00:41
Vauxhall Cavalier 2.0 CDX 1995 - Coolant Level Sensor -how does it work - peter973

Within the float is a magnet.As the coolant level rises or falls this magnet operates a reed switch (open/closed) which in turn signals the warning light circuit.hth

I've tested it & it's working ok.

In fact when you move the float up & down you can hear a slight click as the switch is operated. I've also tested it on a multimeter.

What confused me when I first tested it on the car, was that with the sensor out of the bottle, the coolant low level warning lamp was on, I moved the float up, the warning lamp did not go off.

I now realise the Check Control System which controls the lamp, only checks the status of the sensor when you first switch on the ignition, not later when I had manually moved the float by hand.

Thanks

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Tue 1 May 2012 17:29
Vauxhall Cavalier 2.0 CDX 1995 - Coolant Level Sensor -how does it work - peter973

Does anyone know how the Coolant Level Sensor works ??

It is integral with the coolant expansion tank cap.
( I will post a picture later of the cap & sensor)

Here are some photos.

http://i422.photobucket.com/albums/pp303/93728/DSCF0472.jpg

http://i422.photobucket.com/albums/pp303/93728/DSCF0476.jpg

http://i422.photobucket.com/albums/pp303/93728/DSCF0485.jpg

Edited by peter973 on 01/05/2012 at 17:32

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