bigred0605

I have an 07 fx4, when I start it up the a/c blows nice and cold. Then after about a minute or two, it starts to blow hot. But after another minute it will start to blow cold again, and everything if fine. Any suggestions to what could be wrong??

Chacka

My truck is doing the same thing. I am thinking either heat saturation or the pressure cycling switch is going bad.

bigred0605

It usually starts after I pull out of my driveway. Maybe I should sit there for a little while and let the truck start to warm up and inside cool off.

Chacka

Mine only blows ice cold on max. Granted the cabins are big and the temps here are any where from 102-107 everyday. It works good when its cool out, and when it's on max. Turn it on regular ac and it sucks.

Mod (Ret.)

This can be an issue when idling for a period of time (engine heats up, creating heat at the radiator and heating the AC condensor), or when at WOT (wide open throttle). At idle, not enough air is pulled through the AC condensor/radiator, so the AC will not be cold. At WOT, the compressor is cycled off in order to provide the best accelleration.

Other than having the AC system checked to verify it is up to snuff (correct amount of freon, no leaks, etc) is to install an electric fan arrangement. They pull much more air through the condensor/radiator at idle, and the AC operates much better at idle conditions. A side effect is less paristic drag on the engine, allowing the water pump to last longer (not that it fails early), and some even say they pulled an extra MPG from doing the mod.

I installed an electric fan arrangement on my 4.2 V6 last year. I posted my installation, so if interested, do a search on "electric fan"; you'll find it.

So, when the outside temps are in the 90's plus, and the engine warms up, and your idling, expect the AC to not be as efficiant. Once cruising down the road, it will get better, as more air is running past the condensor/radiator.

I'd get the AC system checked; most service places are offering a free or low cost inspection since it's now summer. Make sure you do not have any issues with the AC system before deciding if an e-fan setup is what you may want to do.