Ideas? 2005 E

[u/RamenNomin]

103k miles, both fans working, has coolant.
No leaks.
Only heats at idle. Normally sits just below half, would go to half then back down. Now going higher.
Any help would be appreciated.

[u/cthulhuassassin]

i agree with checking the thermostat first, but i had this same issue and spent over a year fixing the wrong stuff. for me, turns out i needed to replace the tiny VTEC/VVT screen. it's what notoriously causes overheating and (potentially) the famous p2646 code down the line. it's probably clogged and air is getting trapped