Howdy,

Before I begin I want to let you know I tried searching the forums a number of different ways in an effort to not waste anyone’s time.
My 2000 F350 V10 with 172K miles has a temperature gauge that won’t sit still. I just replaced the thermostat with a new OEM unit and o-ring.
Symptoms:
1. When started cold the temp. gauge instantly jumps up to the “normal” position despite the cold start.
2. When I start driving it will, sometimes, instantly drop to its low point and the red temp light comes on.
3. Not always, but sometimes, when I give it a decent push on the gas pedal it will instantly jump to normal even if the engine has not full warmed up.
4. If I turn the AC on it sometimes causes the temp gauge to drop to its low point and the red light comes on and when turning the AC off it sometimes goes back to its normal position.

With the new thermostat installed and the engine cold I hooked up an Innova meter and watched the temp. gauge while the truck warmed up.
I tried recreating the jumping gauge while in park and all of the symptoms I listed above still exist.

Any help is greatly appreciated.

Thanks,
Neil

P.S. I videoed the temp gauge for four minutes fro cold start to 92 degrees but didn’t post it here. Available if needed.

 

What did you hook the meter up to?