hi gene,
start with the simple, right?

i agree with david burco, check both the accumulator and the line where the orifice tube is located. if they are icing up, then i bet it is the orifice tube clogged up and needing replacement.

matter of fact, i just found the same issue with my 86 245 (swapped out with a 92 ac system). i'll get to it later when it gets cooler here in texas, say 2026? no, probably sometime in october when i can vacuum out the system.

not sure if this is your problem, but with a non-leaking system, it's typical after even 3-4 years after replacing the previous orifice tube.

regards,
byron golden
86 245
92 245
94 940

As others have said - first see if the heater control valve is working properly. May have to replace it. Before I gave up on the Volvo A/C system here in the hot/humid SE and replaced it entirely, I installed a high temp ball valve in one of the heater hoses behind the center console. I did this AFTER I had replaced the heater control valve and still had the same problem. Positioned it so I could reach behind the side panel and open/close it. Each year around March 1, I'd close the valve completely shutting off all flow to the heater core. And come Thanksgiving or so, crack it back open so I could have heat if needed. That gave the OEM A/C a fighting chance during the summer.

you wrote:
Does this sound like a problem with the vent baffles? Using the inside air button makes little difference.


Before you try any of the other complicated suggestions posted here, Make Sure the ReCirc door is actually closing fully and blocking all outside air from entering the cabin.

With the car in a quiet location, start the engine to build up vaccum.
Shut off the engine. Press the ReCirc button and listen. You should hear the door moving into position. Press the button again and the listn for the door to move back into the opened position.

Hi,

The others poster is absolutely correct that your heater valve could be leaking by.
With 190 degrees of hot water available, it can easily overwhelm any A/C system.
This would be my first bet to place on your scenario too!

When you said you have the low side holding in the green zone on the gauge that means that the low side is filled up to the allowed pressure.
That means the evaporator gases are at at temperature of coldness, but that’s it! How much of the evaporator is actually flooded with liquid refrigerant droplets, is another prospect of what is really going on.
Less water gets to go on the fire, per say.

I have pondered the statement about the coldness of a line going “into” the evaporator or cabin.
On these nineties cars, they are all made with an orifice tube expansion device that is not inside the car but outside by the radiator, down low, near the cars frame.
From that point backwards to the cabin it can get somewhat cold. Ideally that should be in the cabin with the evaporator but who’s counting with the bean counters! Being cheap has its drawbacks.
The larger line coming out of the cabin, to the accumulator can, will sweat with condensation and that largest hose going over to the compressor is all part of the low-side.
That is, unless it’s removing a lot of heat from the heater valve!
You see why I pondered the statement ... Which one again?

The orifice is very much the same as a capillary tube system used in domestic refrigerators. It’s just the orifice is a lot shorter and made larger to pass a lot larger quantity of refrigerant around very quickly.
This makes both of these systems an exact “balance” charge system within their operating climate.
On domestic refrigerators wrong charge of one half to one ounce affects its efficiency. Today’s refrigerators have very tiny motors so they run more but consume less energy.
These things are scaled down to a button on a shirt. It just does the job!
These cars go all over the world just like refrigerators.
In both systems, there can be a very slight change in the amount of charge to make the unit perform more efficiently. But in essence, any specifications of charge used are the “best compromise” to get “effective use” where ever the car goes. Heed charge amounts is my best advice.

Now with all that said you may have two things going on, besides a leaky heater valve.
One would be it’s an overcharged system! If you put too much inside, the refrigerant cannot move around to each side quickly enough as there is not enough space left.
You said, it won’t take anymore in, that worries me, but I think you meant by the green gauge zone?

The next thing and this should be highly unlikely, but the orifice itself is becoming clogged up with contamination. They have a screen to catch metallic particles from the compressor or possible coked compressor oil that should be even more rare.
Not to blow all of that out of the water, no pun intended, but I had rust coming from the steel tubes of the condenser coil. Most refrigeration units used copper or aluminum coils except on cheaply made refrigerators and apparently automobiles! This was a real curve ball for me to find!
I surmise that the previous owner of my car had the system recharged and that person didn’t evacuate and dry out the system or put in wet refrigerant and this cause the condenser tubes to rust.
It took 15 years for this to take affect, regardless, I had a good tablespoon of brown rust clog the orifice tube twice before I figured out what the mysterious stuff was.

You should pull the left side console cover and feel the heater valve lines to make sure that both sides are not exhibiting heat when the car is up to operating temperature.
A trickle-by means a lot!

Phil

Seen this.heater core and evap common plenium.air flows through evap first then heater core.had a pd4501 aka scenicruiser bus.when a/c in use the air temp was controlled by hot water flow in heater core. 240 same system except 45 degree rainy weather running a/c is remove moisture.adjust flow in heater core for desired temp.use for quick defog of windshield.warm air with low humidity.check heat control valve closed.had a few customers went to shyster shops were told big$$$to fix.showed them heat valve wasnt fully closed.

Make sure the condenser is clean.

Also, I noticed a significant improvement in the ac in my car after replacing a slipping harmonic balancer. I heard a chirping sound when starting the car and when starting from a stop. To check the harmonic balancer, I put a mark using white out on the inside and outside of the face of the pulley. I drove the car for awhile and checked to see if the marks were still lined up. They weren't.