A/C output could be stronger

[steelerguy]

99 Durango, 5.9 with front air only (also has the little blower fan above the back seat).

We just hit our monsoon season here in Phoenix AZ & I noticed a decline in the coolness of the AC. Humidity goes up significantly when this happens. It's 105 to 110 degrees with a haze & you could just kill people from the oppressiveness of it all, so don't kid yourself about it being a "dry heat" in Arizona. This lasts until about September 15th.

I also recently flushed the cooling system, changed the thermostat & cooling hoses as a preventive measure. The decline happened a few days after (in coincidence with monsoon) & I thought, "well I've never charged the AC" so I bought a charger with a gage & a bottle of the new synthetic freon.

Hooked the charger up without the freon attached & the gage read in the high side of the yellow a little over 55 psi just 5 or so psi short of danger. It's the caution region.

I decided to bleed it down to the top of the blue full indication (45 psi) & it did immediately improve the coolness though not to where it was before the monsoon. That was yesterday & it seemed to improve a good bit as I finished my morning commute of about 30 miles with the last 20 on the highway. I would say it's almost passable but not back to where it was.

I'm think of bleeding off a little bit more & seeing what happens. Don't know if it's hard on the system to do this without a closed loop hookup with manifold gages.

Any ideas?

Anyone have experience with the new synthetic R134A? The counter person at autozone said it mixes with the existing system without a problem. There is no warning on the can one way or another. Like I said, I have not pierced the can yet.

I was thinking of having the system checked, evacuated & refilled with the new stuff & was wondering about what you should pay. I will probably use an AC specialty shop in an industrial park that I used for my on 89 chevy pickup. I don't trust most mechanics, particularly when it gets hot & they know they can charge more.


Update: It appears that the system has stabilized itself during my drive home. Apparently, the bleeding off of the additional pressure has worked. I have never had a thermometer in the vents but would describe the current temperature as "ice cold air".

This strange because at ambient temperatures of 105, the 55psi is supposed to be okay per the directions that came with the gage. I'm glad that I bled off the pressure before I read them or I might not have done it.