Ok everyone, heres one for ya. 2004 F-150 FX-4 5.4 92,000 mi. Just drained and flushed coolant, replaced w/ 50/50 Motorcraft gold. Did everything right(I think!) Water temp guage allways sat right in the middle and NEVER moved after warm up since truck was new. Now after changing out coolant, guage moves around between 1/4 and 1/2 marks while driving, never staying put like it used to. Anyone have any ideas as to why this would happen? Thanks for any input!

 

probably have air in the system

 

Thanks for your response. Now how do I go about getting that air out. Is there a bleeder valve somewhere or somthing?

 

Really shouldn't make a difference with the factory gauge, or do you have an aftermarket gauge. The factory gauge picks up an electronic signal that does not change unless the engine temperatures reaches an abnormal temp..They all read the same, right in the middle of the gauge.

 

Marc: It is a factory gauge. And yes, it used to stay right in the middle. but after coolant flush and change it moves between 1/4 and 1/2. Cruse down the highway and its at halfway mark, Stop at redlight and it starts moving down to right around 1/4 mark. Stays tward the cool side around town.

 

Change the thermostat.