would love some help with this prob
truck over heats on highway only
when it does so the oil pressure gauge rises at the same time
not sure if just the fact that the engine is overheating is causing the oil gauge rise?
everything was fine up till a few days ago i drained the coolant and flushed the heater core to try to improve heat. Heat has sucked for a while. but i can live with that
when im driving in the city it doesnt overheat but temp gauge seems twitchy when i accelerate it moves up just a bit . normally it is solid never moves around at all
and it seems to warm up quicker than normal now
i have done many repairs on my truck myself fairly competent mechanic
-thermostat is new (couple weeks ) seems to open
-it is truly overheating , i pulled over on the highway and the coolant was bubbling.
-surface temp of upper rad hose is 180 lower rad hose about 95 after running for a while
- clutch fan seems to work . Seems, not 100% on this one
- and im unsure of the state of the water pump and how to check without removing
- ive checked the oil on the dipstick for antifreze but my coolant levels are not budging
i really would like to figure this out without having to chang parts for nothing
ive used this forum for many repairs . this is the first time im posting something
i would greatly appreciate any help to keep my f150 going a little longer
shes about 250000 miles still a lot of factory parts on there

 

Had this problem on another ford after doing head gaskets. With these coolant boxes away from the radiator it is very hard to get the air out of the system. Open the lid let it idle and keep adding fliud. Keep an eye on the bottom hose with the cap on the coolant resivor the one I was working on the hose would collasp when it started to over heat.
Hope this helps.

 

did the overheating occure right after the flush and refill ? IF so, i would agree with the ari inthe system. I put a flush TEE in the heater hose up high so i can vent off air when filling the radiator..... did the overheating occure after the thermostat change ? Some new thermostats can stick and cause the problem. If your not bubbling over or loosing antifreeze, then probalby not a head gasket. When truck sets overnight, it starts up and runs smooth the next morning ? No antifreeze leaked into the cylinder ovenight, right ?

 

thanks for the replies i appreciate the help
-the overheating did occur the next time i went on the highway after the flush
-no overheating after thermo change
-overnight the trucks starts same as always.
one big question i have is did the oil pressure rise beacause the coolant was overheating
and tonight i did notice that when i felt the hoses going to the heater core in was hot an out was cold . after i did the flush in was hot and out was warmish
so i know my core sucks but this leads me to believe i have some crap in there moving around but not sure.
and im also curious how can i tell if my water pump is working well without removing after seeing some of the pics of pumps on here im kinda concerned cause mine has 250000 miles .

 

For what its worth I worked on a Ranger that had a loose negitive cable connection on the engine block, it caused both temp and oil pressure to climb to erregular readings. Now if you can get your hands on a scan tool that will read the pids of the engine while its running then monitor the ECT (engine cooling temp) and see if it corasponds with what your temp gauge is doing. And are you using a 50/50 mix of coolant, too little coolant could be freezing the radiator. (depending how cold it is where your at) Also a common mistake of DIY's I have found they put the t-stat in backwards... just a thought.