2006 5.0 GXI F temperature swings

[06dpsm]

I've had the boat for about a year, and never noticed any other reading other than about 155 (3/8 guage). Lately it's been swinging between 155 and 175, up over maybe 10 minutes, then back down again, then up, etc.

Normal and I just never noticed ? Sticking thermostat? or RW pump starting to go? or something else.

Just wondering if it a pending larger problem.

 

[Bondo]

Ayuh,.... Probably just the t-stat cyclin',....

How long has it been since ya change the impeller,..??
That's Always the 1st place to look in any overheat situation, though yer not really overheatin',...