cooling issue

My truck is getting hot at highway speeds. Around town it runs cool, no problem. Its only driving on the interstate around 3g on the tac.

I replaced the water pump and put in a new 180* t-stat. The previous owner took the t-stat out.

i would check the coolant and flush the radiator. also check the clutch on the fan.

flushed the radiator... haven't drivin on the highway yet. but, how would the clutch on the fan make a difference at highway speed? I'm not trying to say your wrong, I'm open to any/all ideas... but at highway speeds, shouldn't the speed of the truck push enough air through the radiator?

so, recap:
New water pump
New 180* t-stat
flush with new coolant (though, i haven't driven on the highway yet)

I think my next step will be to get the radiator refurbished. I know a guy that completely overhaul's the radiator for $40, way cheaper then a new one.

Any other suggestions?

it is heat type thing not a speed type thing. it should be spining faster at high speeds and temps but if the clutch is bad then it will not be spining fast enough and no there is not enough air going through it at highway speeds. also check for bent fins and if there is any junk in them. even a little bit will make a differance.

ok, maybe these trucks work different... but i've driven trucks going 30-40 with no fan (e-fan malfunction) and it cooled the truck down and was drivable as long as you didn't come to a stop for any extended period of time.

Have your timing checked mine does the same thing never use to until I had a front main put in and the mechanic got the belt off a tooth now it runs lean and gets hot at highway speed and cool just a bit above normal in town.

I've experienced the same thing. IF the cooling system is in good working order, there is enough air moving thru the radiator to keep the engine cool (assuming to issues with the engine, i.e.timing, etc.)

IF the radiator is partially clogged and the engine is not working very hard (city driving), then the radiator and fan might be enough to keep things cool. Running 3g on the highway against the wind and your working that little motor pretty hard (and need all the radiator you can get)

Good luck with the cooling issues.

timing is my next check... I just haven't had the time to check it.