[Graeme1975]

Hi there, my first reaction was to replace the thermostat as this is a cheap item to change but i cannot seem to locate the thermostat, its not where i would expect it to be. It is a 2005 1.6 zetec focus. Also i am not entirely convinced the car is actually overheating, the gauge is jumping about in large leaps going from the normal mid position right to the top in one swift movement, if i stop the car and turn off the ignition then back on sometimes the gauge is back to the mid position but not always. The last time i drove the car though it sat right at the top for maybe a mile and did not go back to mid when i stopped and restarted car, i still did not think the engine was overly hot considering the gauge was hard pegged at the top. Thanks for any guidance it is much appreciated from this newbie!

 

[whynotthinkwhynot]

Do you know anyone that has an infrared thermometer? You might be able to do this with a cooking thermometer if it goes down to the right temp. Anyway, shoot the infrared thermo on the upper radiator hose, and if you have to use a cooking thermometer- tape it securely to the upper hose, drive, then check it while the engine idles. You should be able to see if it's really overheating.

I wouldn't think it was. This is a classic sign of a bad temperature sensor, or crossed wiring. I'd trace down the harness that the temp sensor goes into, and inspect the wiring until it's out of harms way. Then replace that temp sensor, and that should be the end of that. If you're wondering what sort of wacky temps it's actually reading- search online for "Ford Focus Electronic Odometer Test Mode" and you should find some sites directing you how to perform that function. I've read how to do it on Fords across the pond before, but I can't remember off the top of my head. I do think it's slightly different than the US models. You're welcome to try our method : Electronic Odometer trick, it might work. Anyway, you can use that test mode to find a readout that will give you the temp in C that the sensor is putting out. If you see any funny stuff- like it suddenly reads 200C, the drops back to 105C, then you know it's bonkers!