No secret the air conditioning sucks the big one on this gen of trucks for some reason. Never had another vehicle where is was this bad. 115 our yesterday and I get a ice cold 89 degrees from my ac vents.......... so I thought I would keep a log of what I have done/doing to find out the root of the issue.

My pressures are good checked last night at 95 ambient and got 40/245

I have added fans to the condenser that run off a trigger wire on the hvac blower in the cabin. They where only on when the compressor fired but there was a negligible difference. Always on made a small improvement when it was only in the 90s.

I have checked the blend door and it is calibrated.

I get a ever so slightly cooler charge when the max ac is NOT on, and strangely enough at one point randomly I will get a super cold gust of air, I'm talking 32 degrees for a couple seconds tops just enough to get your attention. When it's in the low 90s I can get 60s out of the vents. (All temps are verified)

So my plan for this week is to clean out the drain, pull the blower fan and see if the box could used vacuumed out and try a shut off valve for the heater core. Any other ideas that you can think of to throw in the mix?

 

Well, that is a 26 degree drop in temperature. I'm not sure the AC was designed to work in that temperature. I usually see about 50 psig suction side pressure while idling.

 

Of course it was designed to work in that temp, it's just that there is a limit to how much it can do even when working properly. You'd expect to see a 30-40 degree drop in temp across the evaporator core if the refrigeration section of the system is working well. That's why you drive for a bit with the windows open when the interior is extremely hot to expel the hot air, then switch to the recirc mode.

There is a problem with your temperature blend door. A low pressure of 40 psi implies an evaporator temp of around 45°F.

I don't know if your particular truck has a coolant shut-off valve or not. If not, I'd clamp off the hose and see what happens. If there, I'd check and see if it's operational (closing) in the MAX AC position.

 

My ctsv has ice cold ac all summer long out here so I flat out reject the it wasn't made for that idea. The heater core shut off is my next project. Even when you pop the **** off the blend control anything past the stop goes right to heat

 

Got busy this morning and blew out the drain tube, no debris came out so no dice there.

However I also got my shut off valve on the heater core, granted it still early and not the heat of the day but the air is significantly colder I get a consistent 42 degrees out of the vent. With no hot water flowing through the heater core when you flip it over to hot with the ac on there isn't a change in the temp but you can hear air rushing around the blend door. Seems like it's not shutting all the way or the seals are gone.

 

Solid 110 this afternoon and my ac was a consistent 45 out of the vents. Still need better tint to help the cab from getting so hot but it now blows cold with the heater core shut off. Need to do some digging into the blend door when it cools down out for a real fix instead of a work around. But for now getting ready to do it to another truck and see if I get the same results.