84 Mustang 5.0. Temp gauge was barely coming off the cold mark. Put in a new (cheap) sensor from Rock Auto. Now gauge goes to the top end of the normal range. I’m thinking that maybe if I pay more than $1.50 for a sensor I might get a more accurate reading. Any thoughts?

 

Yeah, well, no, those sensors are supposed to work in a certain range. It's possible you got a bad one out of the box, and maybe just get another one and there it'd go.

Having said that, I might be more interested in knowing for sure what the actual temperature was, so I'd maybe be replacing it temporarily/adding permanently a matched sensor and temp gauge that can sit under the hood with the engine. That way you'd be ensured it's NOT the engine overheating or underheating... or one'd hope...

Beyond that... it's possible. But then it's equally possible the gauge is not happy at all and that's why you're getting that issue. Hence the 'for sure' part first.

Don't suppose you maybe flipped your thermostat upside down when replacing? That might cause some of this... air in the system might too... Just thinkin aloud on that... Otherwise... hm. Voltage or ground or something?

 

Thanks houtex. I don’t know the actual temperature, but when the gauge is reading high the engine is clearly not overheated. The gauge only recently started acting up and nothing had been done to the thermostat or coolant level so I don’t think that’s the cause. I think I’ll try another sensor before getting too carried away. Maybe go up to the $5.00 model.