running hot on the freeway
 

searched and found nothing useful. help please.

i have an 01.5 3500 drw. noticed the other day while driving to work that the ac would blow warm while sitting stop lights. then when back up to speed it would blow cold again. then yesterday no ac at all and the truck ran hot onthe freeway. i am leaning on the fan clutch.
thoughts?
thanks.
[coffee]

Have you made sure there is no obstruction between radiator, charge air cooler and the A/C condensor? The puke bottle vapors can end up plugging the radiator then it collects a lot of dirt.
The A/C might be low on charge or the blend door could not be functioning.

Most likely one of two things is happening..... Either the clutch fan is toast and you can usually tell if it is simply by grabbing it (with the engine OFF) and moving/wiggling it around. If there's ANY forward/backward movement and it feels sloppy or if when you turn it by hand (again, engine OFF) and the fan offers no resistance and spins freely. Those are generally signs of a non-functioning fan clutch. If it is bad then note that the over the counter parts store clutch fans are no match for the OEM versions.

Or, if you have never relocated the engine blowby vent catch bottle hanging in front of the engine then the oily vapors have eventually clogged up enough of the radiator blocking the air flow unless you're speeding along down the highway. If thats the case then removing the radiator is usually best because trying to spray with a hose through the condenser and intercooler first doesn't seem to work very well. And pressure washers are too dangerous because you'll easily flatten the fins if spraying too close. Also, if you're going to try and visually look for the oily debris blockage before establishing if you should remove the radiator, its not that easy to see.