Ford Fiesta temperature guage (maybe ?)

[BazzaS]

The car is a 1993 Fiesta 1.1 (HCS engine).
Last night my daughter said that the temperature guage was nudging the red - 'it just happened' and there were no other characteristics. This morning I checked the coolant level - a bit down but still above the 'min'; likewise the oil level - I topped both up. There were no wet patches under the car. When I turned on the ignition the temperature guage went immediately to the middle of the 'norm' scale (this is its normal position when warm). I drove the car and indeed the temperature guage went up to just below the red mark. With further driving it wavered at the top end of the 'norm' scale. I stopped and felt the hoses which didn't seem unduly hot. I came home and tested the fan by direct wiring to the battery - OK. Thermostat and fan sender unit tested OK per Haynes manual. So, I've a feeling that the problem is with the guage rather than the cooling system.
Help can anyone advise what I might do next ?
Thanks

 

[jime17]

maybe you could take it on a run and then checkthe coolant temp with a thermometer? i'd say it should be typically at about 80 - 90 degrees C. take it in the header tank and try and drain some off from the rad if you can and get an average. be careful though!

or go to a breakers, get a gugue from an identical and run a lead from the battery, through the sender and through the gauge and back to neg. i'd havethought that should allow you to check the reading on that one before you have the dash in bits.

 

[jonnyfishing]

Try pulling the single wire from the temp.sender switch and earth it with the ignition turned on.The gauge should go up into the red (max),unearth it and it should fall to zero,if so, change the sender switch

 

[ratm]

Had same problem on 96 1.8D escort. Replace the sender.

 

[BazzaS]

Thanks chaps, yes it was the temperature gauge sender which I've replaced (I've also learned how to spell gauge!).
Regards