Why is my temperature not reading?
Asked by GuruF4YMQ Apr 11, 2020 at 05:37 PM about the 1991 Ford F-150 XLT Lariat Extended Cab SB
Question type: General
1991 Ford F150 5.0
My tempature gauge reads randomly.
Usually doesnt go over the cold line. Rarely goes to
normal temp. Cant seem to find problem
Issues started after changing thermostat.
New sending unit sensor
New temp sensor
And when i grounded the sending unit wire gauge
went to hot. So im assuming it works fine.
Possible the thermostat isnt sitting right?
4 Answers
Did you buy a 195°F thermostat? That's what should be in there. Also, see if there's a bypass valve at the thermostat housing. My 94 Escort had one that got stuck open and caused an "overcooling" condition. It's supposed to direct coolant directly to the heater core when the engine is cold. When the engine warms up and the thermostat opens the valve is supposed to close. Hope that helps! Jim
Try checking the temperature sending sensor with a multi-meter. How to video on the net. Check the electrical connection to the sendor for crack wire or corroded connection.
Fixed so far! Thermostat stuck open within a week of putting in. Also the main reason i changed it the second time was because it was a lower temp thermostat so it was reading lower than factory. Sk i changed it and had this problem. And now fixed. Thankyou
Awesome!! Thanks for letting us know!! You're welcome! Glad to help! Jim
