A/C temp at the vent
 

Anybody ever check to see what temp the air comes out of the vent at. Mine comes out at 72degrees, it seems a bit warm to me.

A/C is designed to run at 55 degree discharge air, there are quite a few reasons yours is high. dirty condensing coil infront or sometimes behind your radiator; wash it out good with a hose. Clogged or very dirty air filters for the evap coil for the front of your truck and the bunk area. You may be short refrigerant in the system, have it leaked checked and the leak repaired and system recharged. Loose a/c belt, also while checking the air filters look at the coils and see if they are matted with dirt, I guarantee if the filter is filthy the coil is also; blow it out with a air hose(not easy to do sometimes). Brush the dirt off before you blow it out so as not to blow more dirt firther into the coil. Keep your face away while blowing it out, your face will turn brown like me, and check to see that your fan runs in all three speeds, if not if you at least have high speed you'll be in good shape, also is the air coming out you a/c vents or out the defroster vents. Check the coils, filters,the fan speeds, the vents, the compressor belt first, then if still no go have the system refrigerant charge checked, leak(s) repaired and recharge system. Open the hood and see if the a/c compressor is cycling on and off rapidly if so it is system charge or dirty coils mainly the condensing coil. ---Good luck and stay cool.

The best you can do is about 17 to 25 degrees below the outside temp. You can check the specs on rooftop units and that's about what they advertise. When the temp was 115 in Las Vegas the other day I was blowing 80 out my vents. The hotter it gets the less efficient the AC will be.

The best you can do is about 17 to 25 degrees below the outside temp. You can check the specs on rooftop units and that's about what they advertise. When the temp was 115 in Las Vegas the other day I was blowing 80 out my vents. The hotter it gets the less efficient the AC will be.

I have a little thermometer at a vent in my KW and it's goes down to 40+ in the recirculate mode on a 95 degree day.

Mine runs around 40 to 45 degrees in my KW, I too have a temp gauge stuck in the vent.

My Ford p/u is usually at 38 degrees

The rooftop unit rocks,..air is 64 degrees (at the vent), and when its 115 here in the Florida sun, the roof unit gets it down to 71 degrees in 20 minutes, then I put the unit on low and it maintains that temp.

Now the cab A/C is only 72, so I'm going to clean the unit up and see how it does.
Thers also a missing bolt on the mounting base. and the compressor shakes around a bit more than it should.

There is also a small tank with a sight glass down on my frame, and it has a couple of quick connects on it, if I move these connects around, I can hear hissing. Does anyone know if this can be plumbed directly, or are the quick disconnects needed?

Do you have coolant valves for your heater? Try closing those, made a HUGE difference with my truck! I guess the in cab controller doesn't totally shut off the flow of coolant.

It was 33 degrees C here, about 91 F. I had my fan on 1/4 speed and it was fine.

Thats the first thing I will check. I remember a few months ago I opened the valve, to check the heater core,....I don't remember if I closed it..

Vent Temp.
 

I bought a small thermometer and placed it inside the vent. Mine stays at 40. However, it does fluctuate after running at 40 for a couple of hours. Some reasons for this are (I think)
1. Air leak from clutch fan
2. Dirty air dryer
3. Bad condenser
4. Super Turbo Cool freon
5. Overcharge
Also my bunk A/C has never worked properly.
My truck is 1998 Frt. Century Class, 370 Series 60 Detroit Diesel

40!!! wow man that's cold, I definitely have to find out whats wrong with this.

Just curious....have you tried the newer freon? its still the 134 but it is supposed to cool quicker and colder. I'm not sure of the name brand of it, but will try to find out soon and get back to you.I purchased mine at Advance Auto and it definitely does get colder.

Are you talking about a refrigerant called; hot shot.

It is called Arctic Cool and it is available at Advance Auto Stores