I have a 2003 F250 with 6.0 and i have been having overheating problems only when in open highway ( in town it doesnt overheat). I have flushed the radiator, placed a thermostat( it overheats with or without it) changed the fan clutch and it doesnt lose water or blow white smoke when I throttle, I also don't lose power when it overheats. Does anyone know what it might be?

 

If it overheats with the thermostat out, I would check the water pump. Sounds like the impeller may have come off or is defective.

 

Well, welcome to the land of the overheating 6.0L! No matter what, just about everyone that has or has had one of these will have this problem sooner or later. First off, look at the exhaust w/motor running. Is it pushing water out (exh. will be wet and white if so). If it is, then you can go further. If you take out the EGR valve (not easy, i know), take a look at the bottom of the intake where the valve sits. If it's wet, it's probably the EGR cooler thats leaking (ultra common problem with these). If it's not, then it's probably the other very common problem of a leaking head or head gasket. I know this sounds serious, and it is, and a lot of work. I would bet good money it's one of these. Also, is the radioator clean?

 

@greasemark, it doesnt push out water or white smoke and no water is missing . @ hanky thanks, thats my next cheaper fix. ill let you guys know by tomorrow

 

No luck with the changing of the water pump. I've been driving in town and it does not heat up but when i hit the open road it does but it does not lose coolant, the only thing next to change is the oil cooler.

 

Have you been able to check the radiator filler neck for bubbles as the engine is going at a high RPM? you are now getting into a possible head gasket or bigger engine problem.
I don't believe the oil cooler could cause an overheating problem like you are describing.

 

Any evidence of excessive of pressure loss or puking out of the degas bottle? White tracking...

 

@hanky, yes when I pull over the coolant is bubbling but I have not lost cooant nor do i need to add cooant. @ Hayapower no pressure lost or white tracking. i'm still puzzed but I am going back to basics and just change the radiator because i did flush it and it has been messed with.


Thanks, norby366.

 

Based on the info you provided , I would suspect a head gasket problem or compression getting into the cooling system. You might be able to confirm this with a pressure test on the cooling system. If it will not hold the pressure that would confirm the suspicion of a possible head gasket problem.
Also if whoever worked on the cooling system may have left the spring out of the lower radiator hose. If this is the case the suction of the water pump at hi RPM will cause the lower hose to collapse and prevent circulation of coolant causing an overheat condition.