Ok, first off Hi, im new here. I drive a 97 Ford Mustang but my mom drives a 95 or 96 Ford F-150. We have been having a problem with it lately. The temp gauge has been going to the hot so we replaced thermostat after thermostat and it still does it. The other day i got in and when i turned the key the temp gauge went straight to the normal zone when i started the truck. The truck was cold it sat for 2-3 days so i know it wasnt warmed up. But ti went straight up to the middle in Normal and when it was warmed up it was on hot. Is there a way i can fix this so we can tell where the temp is acually at cause it makes it really hard to tell if its over heating or not. If you tap the dash sometimes it will go back down to the middle but then jump right back up to the hot zone. I need help this is frustrating me.

 

Have you tried a temp sensor?? What motor in truck?? The 302 and 351 will be on lower intake, and 6cyl(300) will be on side of block..

 

Its the 5.0 so im guessing 302. Im not really a motor person. I can work on them no problem but cant tell you sizes besides Liters. Yea i know its sad. lol

I have not tried the sensor yet. I wasnt sure if that was it cause like i sad the truck can be cold and sat for a day or two and when you start it the temp gauge goes straight to the Normal zone then when the truck warms up it goes to the hot which i guess would be normal since it started out in normal. If that makes since. lol

The truck is a 1995 with a 1996 fuel injected motor. we blew the motor and had this one put in, it has about 70,000 miles on it. What sensor is it and where is it located.

I had a dodge neon and the coolant temp sensor went out on it and the gauge worked fine, it didnt start out in the middle. But it was hard to start till i got the sensor replaced. The truck starts right up no problem.

 

First thing to look at is the installation of this engine. There are bonding wires connecting the engine to the firewall. Easy to overlook or think they are not necessary. Compare to another truck to locate these bonding straps. They maintain and electrical neutral through out the vehicle. Don't think just because the engine is grounded to the battery, everything is good. The entire truck has to be attached electrically.