94 xlt starting to run hot

[dnc8203]

i am new in here but have been doing alot of research about my new x. i had a 91 ranger 4.0 4x4 that i had replaced the head on and traded it for my 94 xlt. so i am very familiar with the motor, but i am stumped. when i got the car it ran fine, changed plugs and wires, oil looked good. the tranny fluid looked good. we went on a trip to my parents last weekend about 70 miles away, everything was fine, until we got to just a very slight incline on the way there. the temp started to come up. i pulled over to make sure it had enough coolant, it did. it was still in the "normal" range but my old ranger never ran that hot. once i made it back home i flushed the radiator with flush solution the best i could. changed thermostat, and filled up with new fluids. it does not heat up to much while i am in town cruising around but as soon as i get on the freeway and start to pull up any incline it starts to heat up again. i just got home and tried spining the fan, it has resistance to it from just being ran so i am assuming the fan clutch is ok. heater blowes hot air. i am stumped, do i need to pull the radiator and have it flushed or might i be looking at head gaskets or at worst a head. worse only cuz its more expensive. anyways thats enough of my life story, any help would be appreciated.

 

[mrboyle]

Temp climbing under load/ speed is often an indicator of a blocked radiator.