aconfer

I have a 2007 F150 5.4 and have always been disappointed in the AC. Especially down here in Florida. I've been doing a lot of research into the issue and I think I have a theory as to why it seems in adequate. Especially at start up and sitting in traffic. My AC works great on the highway and when moving. But sitting, not so much.

I've seen a lot of guys on the forum post things like "the 2007-2008 f150's have a different AC system and isn't as strong as the earlier ones." As far as I can tell the AC systems are identical. But from reading the forums it seems like people are having differing outcomes. My buddy has a 2004 and it blows ice cold air right at start up.

I've noticed that my coolant fan doesn't engage when the AC is on or hardly ever. I've been told that once the engine is heated up you shouldn't be able to turn the fan by hand for the first few minutes after shut down. I was able to rotate the fan so I assumed my clutch had failed and that was causing poor AC performance at low speeds.

Now when i went to go buy a new clutch, there's 2 versions. The pre 2004-2006 trucks were $60 and the 2007-2008 were $250! After some more research, apparently Ford changed the coolant fan clutch from a thermostatic to an electric clutch controlled by the ECM.

In the earlier trucks the fan would engage when fluid in the clutch reached a certain temp. In the new trucks the ECM does it when coolant reaches 210 degrees. I have an edge programer and usually watch the coolant temp. I've only ever seen it reach temps like that on rare occasions. Usually in traffic with a heavy trailer or off road.

My theory is there's not enough air moving over the condenser to result in high performance AC unless moving at a high rate of speed consistently. In the earlier trucks their fan would engage when under the hood temps reached a certain temperature. Not the engine coolant like in 2007+ years.

The 2009+ trucks fix this with a dual electric fan system. One fan comes on with the AC and the other comes on when coolant gets too hot. The pre 2007 trucks would error towards the side of caution and run their fan more often or when under the hood temps rose to a point where the AC wouldn't function properly.

Originally I just said screw it and was going to buy electric fans and do the conversion. But now I'm thinking I can wire in a switch to apply power to the fan clutch when I want extra cooling. There's no way E fans could pull as much air as the stock fan and air shroud.

So could the new electromagnetic radiator fan clutch be the down fall of the 2007-2008 f150 AC?

dssbob

Your theory sounds good. Mine does the same thing. Blows ice cold when moving, then blows warm when at stop lights or slow speeds. I "fixed" the issue by installing a 12" aux efan on the evaporator. I wired it in to the ac lead so that it comes on whenever the ac is turned on. I also installed a cut off toggle switch to turn it off when I'm moving. Works like a champ.

Hongstertruck

Not true because your A/C needed the most during idle and your engine only spins about 700 RPM so still not adequate for the condenser to cool down quick.

A dual fan like a 2010 F150 will pull a total of 60 AMP through the condenser your A/C will have no problem cooling you even at idle. (ask me how I know )

BTW, I did the E-fan conversion. It costed some $550 but all was worth it.

Jkob10

I bought my truck with an Efan conversion and the a/c still does what you described, I guess I have to take a look at it

Hongstertruck

Sorry to hear that. But, can I ask what kind of E-fan conversion do you have? If you have the FORD 2010 F150 dual fan and mated with a reputable controller I would be surprised.