total noob here, posting to see I can figure out what's wrong with my dad's truck.
During city driving it's mostly fine, but the car very slowly heats up (from mid point to the redline of the temp gauge) while climbing long inclines, or driving on the highway from 55mph - 65mph. If I'm going faster or slower, it won't heat up over middle point.
It also won't overheat if I turn the heater on max inside the car, but that's not gonna work out too well in summer
I replaced the Thermostat and flushed the coolant, that didn't seem to help; I thought it could be because I didn't bleed it properly; but it's been a few months now, wouldn't it work the air out itself by this time?
It's almost like for some reason the stock cooling system can't handle the car anymore...
it's a 2.4l 5spd 4x2 XE extended cab. It only has 50,000miles on it, and has been issue free until this.