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AC blows hard, but warm. Coolant pressure is good, blend door seems to be working

My 95 Saturn SL1 has been a real trooper these years. This is the first hvac problem I’ve had.
A couple weeks ago it felt like the ac was starting to go, and by last week it had gone. I figured it probably had a slow leak and just needed a recharge. So I bought a kit from the auto parts shop - for $30, it was worth a try!
The pressure in the system reads full - even a tad high, without putting any gas in!
I double checked everything. Compressor clutch engaged, and the gauge was attached properly.

Inside, I can hear the familiar ‘foop’ when I switch from “hot” to “cold,” which I’m guessing is the air blend door, and the air is noticeably hotter on “hot” mode - so I assume the blend motor is ok.

Any ideas on what might be going on here, or where a well-aimed kick might have an effect?

–Dan

Its time for a trip to a local A/C shop. On occasion the DIY’er can get some more cooling time with those OTC kits, but in general A/C system stuff requires well-trained people with expensive equipment…that is, if you’re sure that the compressor is kicking on…

The AC system in your vehicle is called a CCOT. Cycling Clutch Orifice Tube system. This means there’s an orifice tube with a fine screen filter. And when the low side pressure reads high on this type of AC system, you can bet the orifice tube is plugged. And if that happens, the AC won’t work no matter how much refrigerant is added.

Tester

It’s also possible your charge is too low to cycle the compressor. The gauge on those kits with the color coding tell you what the pressure should be with the system cycling as it should, which is kind of deceptive when your system is too low to cycle the compressor since it will seem as though your system pressure is fine according to the color coding when it is actually very low. You will need somewhere around 80 psi of static pressure (system not running) for the compressor to cycle. If you don’t have that, bring it to that level and see what you get. If you do, it’s off to the a/c shop for you.

As a side note: if you want this problem fixed properly, you need to go to an a/c shop regardless. If you are just trying to scrape by for a little while, it’s worth a shot to try getting it working on your own.

I stand corrected! This AC system doesn’t utilize an orifice tube, but instead an expansion valve. But still, it’s the metering device between the low/high side pressures. So if the low side pressure is high the expansion valve must be faulty.

Tester

Without knowing the static pressure and the high/low pressures it’s near impossible to say.

I don’t know what kind of gauge you’re using but it sounds like a low side only affair?
If there are numerical numbers on the gauge you should see a static pressure reading on the low side of about 120 PSI with the engine and A/C off AND after being allowed to sit for a while to allow the system to stabilize.
(The high side should be the same as the low in this situation.)