Temp Gauge Rises When Motorway Driving

does anybody know of a way of checking the temp sensor? had a look on my parts and maintenance cd, it says to check the resistance. had a look at it this morning and couldnt get a reading on my voltmeter. --

I'm not convinced abuot the oil idea, sounds like typical water pump impellor, Chris has posted this in another thread:

http://www.alfaowner.com/Forum/attac...g?d=1151684768

Engine revs rise and the impeller can't cope with the water pressure so pumps less water round so you engine gets hotter. Same scenario is possible with the oil pump but isn't known.

Could also be your sensor....there's another thread knocking around at the moment...but again, less likely imho.

Hope I'm wrong...

wrinx

checking sensor is very sensible idea, especially when you look at your earlier posting

"just remembered a point with the fault. Once i stop the car and turn off the ignition and then turn it back on again the temp gauge moves back to the 90 degree mark (from full with warning lamp on), once i move off again and regain speed it starts to move up again (depending on the speed being driven at)."

they often fail and give improper readings. resistance is what you should be measuring not volts, resistance will either fall as temp rises or increase (not sure on that exact sensor) but typically they tend to work so resistance falls as temp increases, set your meter to ohms and measure across terminals when it is unplugged.

Hi have you sorted this yet - my 166 3.0 is doing EXACTLY the same thing. I have booked it in for a new water pump next week but at £690 I would rather not do it if I dont have to - I have already replaced the radiator.