Realistic AC expectations please

[desertwampa]

I think we have to remember the rules of A/C systems overall right now.

An A/C system is essentially designed to cool the existing air, about 35 degrees. Most of the systems we see with more than 35 degrees, are mostly new and recently had parts replaced and airflow and gas flow is clear.

At 110 degrees, the most efficient system in anyone's vehicle, is pushing out 75 to 80 degree air.

The best way to really gauge the basic health of the A/C system is to measure the temperature of the vent and compare it to the cabin temperature.

In the file below, you can see on a really humid day with not a really alarming temperature, the vehicle at idle was maintaining ~28 degrees of difference between cabin and A/C air.

View attachment 3749461

Which is a great point, and circles back to the original question. Is it unreasonable to expect cooler air, or better ac performance.

From the replies I've received here and FB, it sounds like a lot of folks have better ac than me, and getting alot cooler than 70 or 80 in 100 temps. Which the goes back to your point about parts replacement or air flow issues. I'll get to the bottom of it eventually

 

[rdcnj]

Which is a great point, and circles back to the original question. Is it unreasonable to expect cooler air, or better ac performance.

From the replies I've received here and FB, it sounds like a lot of folks have better ac than me, and getting alot cooler than 70 or 80 in 100 temps. Which the goes back to your point about parts replacement or air flow issues. I'll get to the bottom of it eventually

Start with the condenser.

If you're keeping the vehicle and want worry free use, I would personally replace:

1. Expansion valve - Recommended as they can get clogged over the years.
2. Evaporator - Not absolutely necessary, but won't hurt
3. Condenser - Absolutely recommended. I have the Nissens unit mentioned.

Especially since we know the compressor is clearly working.

 

[GeoRoss]

I routinely run vent temps below 50° with temps in 110° range. I do have 20k in the fan clutch and rebuilt, flushed my system a few years ago. The only original parts are the lines and evaporator. The rest are OEM replacements. When stopped the temps do rise at these temps, but I don’t sit in a running truck, so not an issue for me.

 

[rdcnj]

I routinely run vent temps below 50° with temps in 110° range. I do have 20k in the fan clutch and rebuilt, flushed my system a few years ago. The only original parts are the lines and evaporator. The rest are OEM replacements. When stopped the temps do rise at these temps, but I don’t sit in a running truck, so not an issue for me.

Once the ambient temp of your cabin lowers from outside temperature to "cooled" cabin temperature, the vent temperature will adjust accordingly.

IE, if it's 80 in your cab and 110 outside, your vent temps should be in the 50 or sub 50 range. Its why on long highway drives, you feel like you're in a refrigerator. You kinda are, albeit a poorly sealed one.