I know there are a lot of posts about A/C not working well in these trucks, and i have seen many different things to try, but wanted to throw my scenario out there to see if anyone has any advice.

I got this truck in 2012 used, and the A/C has never worked well when I am idling, when I am moving, it keeps the cabin comfortable, but as soon as i idle, the temp starts creeping up.

What I have tried

• Replacing the Fan Clutch (Mechanic 1, Summer 2014) - The first time i brought this issue up to a mechanic, they said the fan clutch was bad and replaced it. Started blowing hot again at a red light right after i left..
• Replace the Schrader Valve on the Low/High side (Mechanic 2, Summer 2017) - The second time i brought this up the mechanic replaced both Schrader Valves on the High/Low side hookups. Same thing, left, went to a restaurant, sat in a parking lot to see if it worked, and it started blowing hot again...
• Cleaning the Condenser and Radiator (Me, July 2019) (Why didn't any of the mechanics before mention this, idk...) - I don't know how the engine wasn't overheating, there was so much dirt and debris that came out. I also added some refrigerant since the low side pressures were in the 20-25 range when it was 100 outside.
• Cleaning the Evap Coil (Me, July 2019) - did the best i can after punching a hole in the box. I did use this opportunity to verify the blend door is working properly.
• Evac and Recharge Properly (Mechanic 3, July 2019) - It was overcharged from me adding refrigerant a few days before.

Long story short, i should have gone back to the first 2 mechanics after their "fixes" didn't last.

So now I am here. When i am driving along, the A/C blows relatively cold (100 outside, 44-48 vent temp). When i come to a stop or I idle, the vent temps will start rising and get into the 80s or 90s. I also notice a lot of condensation on the outlet fins of the vents. Then i start driving again and i starts cooling again.

Today, here was my experience,

• Pulled out of the garage, vent temps were 86, the same temp as the garage, this is to be expected.
• When i got to the main road to go to work (a few stop signs) the vent temps were already down in the high 40s.
• When i got to work (about 10 minutes after pulling out of the garage), the vent temp was 44.
• I sat idle in the parking lot for 15 minutes to see what happened.
  • I could feel the compressor kicking on an off, the vent temps would fluctuate between 54 and 62. This went on for about 5 minutes.
  • Then the compressor turned off for a while and the vent temps got up to 73 degrees (4 degrees warmer than the ambient outside temp). It stayed in the low 70s for about 5 minutes.
  • Then the compressor kicked back on and the vent temps plummeted to 47 degrees and stayed that way for over 5 minutes. Then i had to actually go work.

Long story short, what else can I try to fix this issue, the truck is still in great shape, and i love driving it. The biggest thing for me, we just had our first child over a month ago, and don't want her to risk overheating during these hot Texas summers.

I have had many great recommendations about mechanic 3 from neighbors and family friends, and he has been giving me some DIY things to try (like cleaning out the condenser and such).

Does anyone have any idea what this could be from their experience, I don't want to start playing parts roulette if i don't have to, but i will replace what needs replacing.

I am wondering if there might be a bad pressure sensor on the high or low side, or a bad thermostat on the evap? There is also a significant amount of condensation on the dryer and the cold line coming from it, does that need replaced?

I don't have my own gauges so i can't see what is happening on the high side, but the low side always tends to be in the 20-25 range even when it is 100 outside. According to the Ford charts i have seen, it should be in the 40-50 range at that temperature.

Thanks

 

Seems reasonable to think the thermostat could be malfunctioning. I think there's a relay for the compressor, that could be going bad. Hopefully someone else knows definitively. My '07 never had this issue so I'm not really experienced on it.

 

I am interested to see if others have experienced this and have a fix. Mine will occasionally do the same thing. It will blow cold while moving but sometimes when I come to a stop it will blow warm air until I start moving again.. It can be very annoying especially when it is 100+ outside here in Texas.

 

http://ricksfreeautorepairadvice.com...arm-idle-f150/

Could just be part of the design but mine seems too intermittent

 

These A/C units just aren't that great. Had a leak on my compressor shaft input and decided to just replace the compressor, dryer and orifice tube. Did all the work myself and couldn't get the Freon dialed in so just had a shop do it and now it consistently blows at 44-49 degrees. Just like the factory one. My wifes 06 Yukon will freeze you out and my 08 F150 will keep you comfortable. Had an 05 Lariat before this one and it was the same.

 

Alright, so an update to this. It's better, not perfect. but better.

I ended up having the Compressor, Condenser, Orifice, and dryer changed out. He also did a flush on the system. He also did the serp belt while he had it off. Mechanic gave me a really good deal on the replacement.

When it is working "properly", its awesome, blowing 37-39 while driving and 41-43 when idle. Almost a 10 degree improvement over before.

I did punch a small hole in the box to look/clean the backside of the evap coil and I can see the blend door works properly and the recirc door work properly.

I still have the issue where I drive to work, idle in the parking lot, and it blows warm air (68-73). I checked, the evaporator coil was warm to the touch (measured 71 on the temp gauge), and i felt a small shudder which i assume is the compressor kicking off. Then after a few minutes, I feel that shudder again, then it gets cold (assuming the compressor kicked back on). Once it throws this tantrum, its back to blowing this cold air.

Now i think i need to figure out what is causing the compressor to kick off. What sensors/electric components could cause the AC to kick off in this truck (Manual AC, not Automatic/Dual Climate)? Here is what I know of

• A/C Relay and Diode
• Low Side Pressure Sensor
• High Side Pressure Sensor
• What else?

Can the pressure sensors be replaced without flushing the system?

Are there any other sensors that could cause the AC to cut off? I believe the PCM can control the compressor as well? Are there Temp Sensors anywhere like the evaporator?

The only components i think i have left to replace are the pipes themselves and the evaporator coil. I purchased one of those endoscope cameras and I am going to take a look at the front of the evap coil (I bet is is caked, as i don't feel much air going through the coil, it seems to go around it.)

What is this on the A/C pipe? is it a filter of some sort? Could this be plugged up?



Does anyone know of a slick way to clean the front (toward the firewall) side of the evap coil). I was thinking a long tube on the coil cleaner and go in through the recirc intake.

 

That's an expansion valve, I believe.

 

Have you checked the engine fan clutch?

This would do most of your cooling while at idle ie sitting still. Also the compressor is sized to run at 1500-2000 RPM so when you are at idle 700-800RPM the amount of refrigerant you would be moving is less, so you would have a lower cooling capacity.

 

I have and the fan clutch appears to be good. The fan spins well at idle.

Are there any aftermarket compressors that are better than others? Maybe something that can adjust itself to the room of the engine to produce optimum cooling.

I think I have it as good as it will get. It's blowing 58-62 at idle when it's 100 ambient and driving is 46-48. My wife's Escape blows 46-50 at idle in the same conditions.

It seems like the truck chokes itself on it's hot air (it's sucking back in what it is blowing over the radiator) when standing still.

 

FWIW my '08 blows icy as soon as the truck is moving but on a 90 degree day, if its sitting for very long, it doesn't have much chill to it.