Its been in the mid 90's here and have noticed my A/C has been having trouble keeping up. It will keep the cab cool if its on recirc but take it off and the cab will get a little warm. The truck is 4 years old. Is it time to have the Freon checked?

 

Check/change your cabin filter

 

Changed in April. I usually change it every spring after the pollen has settled down.

 

I have noticed my 2018 a/c slowed up a bit, especially during this year's heat wave. I swapped my cabin filter and it helped. May look into a recharge as well.

 

AC issues can happen at any time or mileage so based on your comment that the unit does not seem to be performing well, yes I would have the system checked. Your refrigerant gas, R134a (not freon) should never need attention unless there is a leak. DONT just "top off" the gas, have it done correctly. If gas is low, you have a leak somewhere. Find it, repair and recharge.

IMPORTANT: Post below states this unit takes the newer R1234YF.

 

A lot has to do with if you leave your truck out in the driveway (sun) or garage it. I garage mine 90% of the time and the A/C works fantastic gets ice cold right away. If I leave it out in the sun, it takes sometimes longer than my trip to get ice-cold for the vents and everything else to shed some heat from sitting there.

 

Before you put a manifold set on your system, clean your evaporator. Takes about 5 minutes to get the coverplate off and grill out. Use non-acidic cleaner, let it soak, gently spray it off. Check for debris between the evaporator and radiator while you've got the cover plate off.

If vent temps are sub-par after this and your fans are operating properly (should be loud anytime it's about 85º or warmer and you start the truck), then it's time to check pressures.

 

condenser

 

Be a little careful what you put in the system.
Page 423 of 2018 Owner manual for 2.7L specs 1234YF. Not any other refrigerant.
It's much more expensive than 134A. Freon is not used in any system.
The A/C system is a Variable Efficiency design.
It's output changes with conditions and reduces load on the engine, at times. This is possibly what you may see and fools you to think there is a low charge condition.
Good luck.

 

Excellent information, especially about the R1234YF. Always check your trucks under the hood label for correct gas and amount!