New A/C not blowing as cold as expected.

So many things . Blocked / Dirty radiator . Will cool better while driving vs idling . Stuck expansion valve. Moisture in system causing expansion valve to freeze up- turn off wait couple minutes turn on works good till freezes up again. Maybe low on Freon or too much Freon . Too much oil in system displacing Freon . High pressure switch problem . Etc need more symptoms

 

Do you have heater shut off valves closed?

 

Raise the rpms and cooling at idle will be just as good as driving. Even better if the fan stays on.

I've done my own ac and i'll freeze on a hot phoenix day. At the rest area

 

As long as radiator fins aren’t plugged blocking air flow

 

All are great suggestions and I concur, these earlier model trucks, if your comparing them with the newer trucks do not have the air volume capacity (design, duct work, vintage blower motors, ect.) I've had these complaints from drivers seat slipping from new to older trucks and this always seems to come up. Shutting down flow to the heater core is a must because the heater core and evaporator are mounted in close proximity to one another separated by a blend door type that might not be sealing off the two from each other like when it was new (dirt, dust, bubble gum wrappers you name it) I always check the cab air filter and clean it for sure but my first question to the driver is what position is the RECIRCULATION switch in on the a/c controller, and invariably always seems to be in the OFF position, that opens another fresh air door that raises the temperature. As I started out with, temps can measure the same at the dash with all being said as equal, but from 2000 to 2018, air volume is entirely a different story. In 2000, that was good stuff, by today's standard marginal. Again I am only going on the premise of your complete inspection.

 

If everything is working properly and fully charged. I get the same vent temp regardless of recirculate or not. And I don't shut off water valves. I get a couple degrees colder with them open. It also helps to keep the evaporator and expansion valve from freezing up.

If the freon gets low. water off and recirculate might help.

I do my own charges. I can get 38 degrees out the vents.

Cars don't have water valves.

 

You say it doesn’t blow enough. Maybe the evaporator is full of dirt blocking air . Take fan out and reach inside wipe dust off and blow w air and clean w anything that doesn’t contain acid or bleach . A lot use brake clean . I like to unless using another cleaner after. Best to use hose and rinse well. Most water will go out drain tube. Best way is take both coils out - a/c evap and heater coil. Clean and install. Not really necessary though garden hose works good. Other than that could be a door stuck half closed caused by an air actuator. Or just a weak fan

 

A little confusing Title states not blowing cold . Description states blowing cold but not enough ( air flow) ?