engine temp sensor

[wcastle]

hello, I just replaced the water pump in my 2005 EB, 5.4l. I let it idle for 30 minutes, then drove it to check for leaks. The temp gauge indiacted hot all of a sudden, and sent the engine into fail-safe mode. i shut the engine down to check coolant level, all was good so I started the engine, the temp was normal. It does this at random now. then my wife called and said the gauge stayed on the cold side. any ideas?

thanks.

 

[Bigdaddyof4]

I kind of had the same situation. It ended up being the CHT sensor with is located on the driver side front in the valley directly under the intake. I had to remove the intake to access the sensor. I had to replace the entire intake because it was cracked at the thermostat housing and leaked on top of the sensor thus causing it to fail. It took me about 8 hours to remove, replace the sensor and intake, and put it all back together again.