08 F150, 406 supercrew 4X4
outside temp in the 85-90 degree range

In the cab with a/c on max with air recirculating on. what should the inside temperature be at the center of the truck?

I am not sure of my A.C is working they way it should. and would like to know about what the inside temp should be before I take it in to be looked at. To me it doesn't seam to be as cold as it was a few months ago.

 

On average, the AC should cool the air about 30 degrees less than the outside temperature. Obviously it will cool better when the truck is in motion, as more air flows over the condensor in front of the radiator. At long periods of idle, the AC will not be as cold. Any AC shop will do a free inspection for you. Take it to one of these shops for "peace of mind".

 

I had a thermometer in my vents on the way home today. I had just serviced the AC this afternoon so I had the correct amount of refrigerant, 1.05 kilos. Outside temp was 86F, Dewpoint 70F, Vent temp 42F.

 

if you have a thermometer stick it IN one of your vents, temp should be between 30-40 no matter how hot it is outsided (atleast in the US)

BTW that is on max ac with the fan all the way up.

 

A tad high for my liking but will do. I try to keep everything around 36. The amount of refrigerant is very touchy, it weighs different depending on the state of the refrigerant( liquid-gas-somewhere inbetween). The best way to determine is pressure compared to ambient temp chart and vent temp assuming good air-flow across evaporator and condensor.

 

how long should the A/C run before the temp drops down to the 30-40 some degree range?

 

I would let it run with the windows up for 5 mins. If you are below 44 you are probably good. Judging by your location you shouldn't be above that. I'm guessing 110 degrees and 80 percent humidity doesn't happen often in MD

 

right now it is 100 percent humidity and 88 degrees

I will check tomorrow when I am in my truck

 

Mass is mass, there is no difference in mass whether its a liquid or gas or even its temperature.
Which weighs more, a pound of nitrogen or a pound of helium?
They both weigh a pound

You may be thinking of Thermostatic Expansion but the Mass never changes unless of course, there is a leak to Atmosphere.

 

My truck cools great. Now. Had to put refrigerant in it. But,when it is 100 degrees ambient temp., my truck cools down to 38 degrees. That's 62 deg. below ambient. BTW,thats not taking the heat index into account. When it's 100 deg.,the index is usually 108 or higher in the sun. Have seen my a/c cool down to 33 now.