I have a 2008 F-250~
This problem has been making me CRAZY Temp gauge registers HOT (even though it is not overheating) icon flag comes on and it says "Reduce Engine Power" It has been in service numerous times they can't seem to figure it out?? (just got it back yesterday) It did it again on my way home from work...Has anyone heard of this problem??

 

Should be throwing a code if its triggering the reduced engine power message. Is the dealer telling you there are no codes? Try another dealer.

 

Had this same EXACT problem when I first bought my truck. The temp gauge would peg only minutes after starting down the road. Threw codes and the overheat message. I knew the engine wasnt hot cause it had only been running for 3-4 minutes. After it pegged, it would eventually go back down. They traced it, FINALLY, to a bad sensor, one of 2 which measures temp coolant. Hope this helps.

 

I need to know what sensors you had to replace because my truck just did this to a tee. It is not over hot but gauge was reading max temp. It is running fine no changes. I need to fix it asap so any help would be appreciated.

 

bad #3 sensor will cuause this and is very common on 08 6.4, for came out with a better sensor later in production.

sensor cost 80 bucks. use a toruch to get the old one off becuase its going to be rusted on

use anti sieze when you install the new one.

like was said earlir.....get the codes read and confirm which sensor...most likely #3