I've posted this question a while back but figured I'd try again. I have a 2006 F150 Lariat Screw and have had a noise coming from the far passanger vent since I got it. It only happens when the air conditioning is on. It's the worse when the temp is in the upper 80's to mid 90's outside but happens all the time. I can hear it best when the fan is between 1-3 bars. The noise is hard to describe, kind of like a hissing and it cycles every 7 seconds or so. It sounds like the compressor is recharging or something. I've taken it to two different dealers, the fist said they couldn't hear it and the second said it is normal. It is annoying as heck and I can make it get louder or cycle longer if I hit the gas hard while it's doing it. Like I said it cycles about every 7-10 seconds and the noise lasts for about 7 seconds. What is causing this? I love the truck but this noise is driving me crazy. The air isn't that cold either. Is there any difference in the AC units of the F150 and the 250 or 350's? is it possible to swap them out to better cool thr truck and maybe get rid of the noise too? Living in Arizona I would pay for the swap out if it were possible and inproved the cooling. Any help is GREATLY appreciated. Thanks.

 

I would replace expansion valve and recharge, ask if you can pay extra for at least one hour on vacuum pump before recharge, any open lines should be sealed if left open for any amount of time. I Always add an Oz of oil and definitely insulate the HP line from condenser to evaporator lower AC line.

Hope this helps

 

You just answered a post from 11 years ago..... That guy hasn't been around in a long time.

 

On the other hand, if he's been waiting 11 years in Arizona with no AC, he's gonna be one happy dude if that advice fixes it. One REALLY REALLY happy dude.