Fluctuations on water temp

[crankedup]

My Bro's RangeRover continues to play up with the temp gauge reading normal and then will suddenly climb into the red. Stop and find all is normal under the bonnet, this keeps occurring any suggestions please? I have also posted this in the BMW forum as the car has the BMW six cylinder diesel engine.

[camel_landy]

Firstly, double check everything with a laser thermometer... This is vital to make sure you're not looking for something that isn't there.

Assuming everything is as it should be, it'll be either your temperature sender of the wiring in between. However, it'll typically be a poor earth to the body, engine or something simple.

M

[crankedup]

Many thanks Camel Landy.

[Nick1point9]

A lot of automotive temperature sensors are NTC, negative temperature coefficient, resistive sensors (monitoring temerature by measuring resistance of the sensor). Sounds like there could be a short to earth somewhere based on that.

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Nick1point9 said:

A lot of automotive temperature sensors are NTC, negative temperature coefficient, resistive sensors (monitoring temerature by measuring resistance of the sensor). Sounds like there could be a short to earth somewhere based on that.

New temp sensor fitted wiring checked and he is still having same trouble. Tried my two independent garages booking in for work to be done, both refused the work with much sucking of breath in between teeth, muttering P38's. Never known either garage to do this in the ten years I have taken all manner of cars to them for repairs.
Are these cars really that bad to work on?

[Xtriple129]

Whereabouts in the country are you? There's a chap down here in the southwest that knows those bloody things like the back of his hand and works on road and race RR's constantly.

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My Bro' is in Watton, Norfolk. Bit to far from S.W. I expect.