Hi all,
I've been having a problem with the temperature display on my Fiesta XR2i 1991 (CVH). It seems to only work when it feels like it and is not consistence. Might work tomorrow but then won't work for a week, for example. It justs gives a below minimum reading if that makes sense, ie it stays at the bottom level as if you had the ignition off.
I have replaced the thermostat, after advise from a prior thread, but to no success. I just want to know what else it could be. I'm thinking it could be the sender unit but am not sure if I have located it correctly. Is it the screw type device near the thermostat housing which when unscrewed from the head is about 2 inches long with a copper end that goes into the cylinder head?
Or could it be the Temperature Gauge and if so does this refer to the actual instrument in the dash? Any assistance greatly appriciated.
Steveo
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I would be tempted to try the temperature sender next. I didn't see your previous post about this problem but from the symptoms that you describe I think that the advice you received about changing the thermostat was somewhat off the mark. Anyway Fords do have a bit of a reputation for eating temperature senders (in my experience) and changing this first will be a lot easier than having a go at messing around with the clocks. I don't know where the temperature sender is on the 1.6 CVH off the top of my head, but I think I am right in saying that there will be two on this engine. One for the dashboard display (the one you should change) and one for the engine management (the one you should leave alone). Have you got a Haynes manual to consult? If not I'm sure there will be someone along in a short while to tell you which is the correct one.
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On early cars the temperature gauge has constant regulated +ve voltage to one end, and the other goes into the temperature sensor (its not a sender) where it is variably earthed to the engine body by temperature. The instrument needle works by heating a wire round a bendy metalic strip.
So your temperature sensor will have one wire on it. If you remove the wire and earth it on the engine the gauge should move to full scale. Dont do this for a long time it will burn or damage the instrument.
So if it moves the gauge is ok and its the sensor.
If it dont move it could be gauge or engine earth or voltage regulator (which normally screws the fuel gauge as well)
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Many Tanks Guys.
Very Helpful indeed. Sounds like from what you are saying it could be the sensor as the fuel gauge is ok and I have recently replaced the voltage reg pack on the alternator. Just a quick question when you mention earth the sensor wire to the engine do you mean just touch a bare piece of the chassis with the wire or touch an earth strap or similar on the engine?
Thanks again
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IIRC I read your post on this..Take the lead off the sensor and connect direct to engine Ie any part not plastic..if the guage rises to full/overheating. Its sensor thats gone.thermostat only affects water temp/controls it..sensor should be located at or near thermostat housing.it is screw in.not uncommon on fiesta/any other car..Have doubts its temp guage?
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Steve
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Thanks all for the advise. Helpful as usual.
Cheers
Steveo
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You can check your thermostat by putting your hand on the top hose;when you first start the engine,it will be cold,then after 2 to 5 minutes it will suddenly get hot-if it gets hot slowly you have no thermostat or a big leak past it.Turn the heater off while you're doing this.
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Be sure to note the colour of the band around the top of the sensor when you go to by a new one. I had one of these things go on my Escort. Funny thing was, it still had varying resistance with temperature.
It was a bit of a gamble locating the right sender, I forget the colours now, but it was something like I had a purple band, and they had a choice of green or black! :-)
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