110 19J Temperature Gauge Reading High

Landysteve9607 · 2025-07-05T20:22:24+0100

As per title my 1989 19J the gauge is reading at the very near end of the white scale, just replaced the head gasket twice (dont even go there ! ) its not boiling over tried a digital thermometer not even 70c at thermostat and 60c at head 70c at the block. I would like to know if anyone has still got the 19J and what their temp gauge reads. Have also replaced the temp sensor to no avail.

miktdish · 2025-07-05T20:59:02+0100

Temp gauges are relatively simple things, they are reading a resistance derrived from a thermistor that gets lower in resistance as it gets hotter.
There is a single wire to the 'sensor' which is effectively grounded through the sensor/thermistor to the engine.

So - what can go wrong ...

The engine needs a good ground path back to Negative on the battery.
The sensor needs a good contact to the engine block. Dont fit PTFE tape on the sensor.
The gauge needs to 'match' the sensor (i'm not sure if there are different ones for the S111, there are for the 200 and 300tdi)
To test the sensor you need a digital multi meter that measures Ohms

Cold the sensor should read 880 Ohms.
At temperature (approx 75C) the reading should be 71Ohms.

To test the meter, take the wire off the sensor and touch it to the engine and the gauge should go to the HOT end of the scale.
If you can find a spare 'Dash Bulb' (a 2W bulb) the resistance would be around 72Ohms which would put your gauge in the 'normal' range.

Hope that helps.

Landysteve9607 · 2025-07-06T08:50:14+0100

miktdish said:
Temp gauges are relatively simple things, they are reading a resistance derrived from a thermistor that gets lower in resistance as it gets hotter.
There is a single wire to the 'sensor' which is effectively grounded through the sensor/thermistor to the engine.

So - what can go wrong ...

The engine needs a good ground path back to Negative on the battery.
The sensor needs a good contact to the engine block. Dont fit PTFE tape on the sensor.
The gauge needs to 'match' the sensor (i'm not sure if there are different ones for the S111, there are for the 200 and 300tdi)
To test the sensor you need a digital multi meter that measures Ohms

Cold the sensor should read 880 Ohms.
At temperature (approx 75C) the reading should be 71Ohms.

To test the meter, take the wire off the sensor and touch it to the engine and the gauge should go to the HOT end of the scale.
If you can find a spare 'Dash Bulb' (a 2W bulb) the resistance would be around 72Ohms which would put your gauge in the 'normal' range.

Hope that helps.

Hi Thanks for your reply I will try that today and let you know the outcome.

110 19J Temperature Gauge Reading High

Landysteve9607

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miktdish

Guns n Chainsaws

Landysteve9607

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