Mod (Ret.)

The AC blows cold in my truck while I'm cruising or moderatly accellerating. If I accellerate hard (push the gas pedal down), then yes, my AC cooling temps change too (vents blow air, but not as cold). As soon as I settle back to cruising, the cold air resumes.

This was common in the earlier days of "dinosaur" AC compressors, as they where piston types; they required a lot more "grunt" to operate. The newer rotory style AC compressors used today are much less power robbing, so I was supprised to see that my AC did cut out when I was asking for "above normal" accelleration.

I figure it's normal, as my AC blows cold, as long as I'm not sitting at a stop light or sitting still (idling), as the AC condensor in front of the radiator cannot expell the heat without a good flow of air (fan will not keep up for long if you're sitting still for too long a period).

However, I have a 4.2 V6, not as "powerful" as the 5.4, so I would also think that the 5.4 should be able to handle your accelleration needs as well as the AC compressor just fine.

A quick call to your Ford service department should be able to confirm this. Let us know.

bfdtpkt

I also believe NAGATA is absolutely correct!
I don't know where I read or heard this about the compressor backing off on WOT but my '05 5.4 has always done this.

Look at the up-side, it has to add to mpg!
Having said that, when I drove my XLT out of the new-car showroom I complained about the a/c not being strong......
the service writer chuckled and said there is no problem.......

BUT, it does not blow as cold as my PATHFINDER OR GRAND PRIX GTP!
I've obviously gotten use to it and have no complaints, especially at the current 97,000 miles and the a/c has never been serviced.

nagata

Glad to provide some input


I believe the 04-08 F-150s all had relatively lackluster A/C systems, and I'm not sure why. They get the job done, but they certainly don't turn the cabin into a freezer. The 06 F-150 w/ 5.4L that I used to drive for work didn't seem to have a very good A/C system, and my boss disliked it so much that he had it to 3 different dealers checking it out. Each one said that it was working normally, and that while such complaints were very common, that's just how all 04-08 F-150s were. My 08 does okay, it'll get nice and cool, but I must say that my 03 ZX2's A/C system definitely does a better job of making the cabin COLD if I want it to.

NHSD

I finally got around to taking my 2008 5.4 SuperCrew in to have some stuff done and asked them to check the A/C. It never blows really cold, but when sitting at idle it pretty much gives up when the temps are in the mid 80s or higher. Once you get going it improves, but at no time does it give really cold air like my wife's 2003 Ford Escape 6 cyl. Anyway, I get it back and the service papers say it was checked and is operating as it should, so I decide to talk to the service guy. He gets the mechanic and we have a friendly conversation. They admit that the F150 A/C sucks, especially at idle. The mechanic proceeds to say that the fan doesn't blow enough air across the condensor to allow it to work at idle. No idea why their A/Cs just weak overall but that is why they don't function at idle. As to the idle testing results he tells me that Ford requires them to test the A/C by setting it on Max A/C and running the engine at 1200 RPMs. At that speed the fan blows enough for the condensor to function. He stated that there is a TSB for hot and humid areas of the country (he said Texas) where Ford will replace the water pump pulley with a smaller one so that it, and therefore the fan, will spin faster. He also said that they would not pay to do that TSB in Pennsylvania. When I mentioned the Escape being better both he and the service rep immediately said that was because the Escape had electric fans that generated sufficient air flow at idle (again, no justification for why the A/C on the Escape just works better). Now personally I would think a truck with a nice big V8 would come with a nice big compressor and the ability to run it and the last thing that I would bitch about is the A/C. In general this has been a very cool summer here in PA so I haven't have many days where the A/C couldn't keep up, but once it gets into the 90's (not a rare occurance in normal years) it just can't really keep that truck cool in normal non-highway driving - stop and go with speeds seldom over 40 and some degree of sitting and idling.

Anyway, just my bitch and wondering what others experience is and any thoughts or suggestions or I should just stop whining ;-)

nagata

Sounds like a pretty logical explanation to me. Vehicles with electric fans generally have a dedicated A/C fan, or the fan "revs up" to a higher speed when the A/C is turned on, thereby pulling enough air through the coils of the condenser to cool it off and keep your cab cool. With the F-150 and its belt driven fan, that's not the case, unfortunately. Not sure why Ford would not have accounted for this better, but alas, such is the case.

One solution you could try would be to replace the stock fan with a nice, big, high capacity electric fan, or even a double fan (1 for regular cooling, and one for extra airflow when you turn on the A/C). You could also try adding an auxillary fan on the front side of the A/C condenser, pushing air back through, and have it turn on when the A/C is on, but pusher fans aren't nearly as effective and there's a possibility that it could actually hinder the cooling ability of the stock fan. Something to think about, anyway...might look into one of those options myself. The added benefit of replacing the stock fan with an electric one is that you gain a couple extra HP from not having the fan's parasitic drag on the engine.

melmann

I have experienced the cool air/warm air phenomenon also. What I discovered had to do with the auto thermostat (inside temperature) setting. At certain temperature settings on a day when it is mild outside, the inside temp would get cool and the system would then blow warm air to raise the inside temp. It drove me crazy until I figured it out. I've never had a vehicle with such a sensitive auto therm system. I just changed the desired temp setting a few degrees in one direction or the other and it remained constant cool or warm. Hope this helps!

Mod (Ret.)

You cannot blame the AC compressor for this; it obviously works fine when you are moving forward (or the engine is rev'd), as air is flowing through the condensor, cooling it off and allowing for the entire AC to work better. Again, no fault with the compressor, as it's job is to compress the freon gas, changing it from a liquid to a gas. The condensor cools the compressed gas (removing heat).

If anything, blame the condensor. When the switch was made from R12 to R134A, the condensors needed to be larger to work as good as the R12 systems did, but they really do not. As we all know, R12 is difficult (and expensive), and your system would need to be evacuated to use R12 (compressor oil is different). I doubt any shop would do this for you anyway.

One fix would be to install an electric fan in front of the condensor to "push" air through it. Some have removed the clutch fan and have gone the route of electric fans all together, claiming a slight increase in HP, and lower cooling temps, plus the AC blows colder during idle. This kits are pricy (assuming you buy a kit); in the $400.00 range. You can piece a kit together yourself and install, plus save a few bucks.

NHSD

Anyone down south had the TSB performed (or heard of it)? Any idea whether there is a down side to running the water pump at the higher speeds that a smaller pulley would generate? Assuming it does a good job and there are not downsides, it seems like it would be the cheapest "fix" around even if Ford won't pay for it. The electric fans seem like what should have been on it all along. Any idea why Ford chose not to use them?($) My previous Dodge V8 had electric fans (a 2000 Dakota).

nagata

Great minds think alike

Fordman08f150

mine does the exact same thing,when im just accelerating normaly the a/c blows air cold enough to freeze your a** off,but when i go to pass someone it starts blowing warmer air,but as soon as i let off the gas it returns to normal.