Blend door problem. You are likely getting heat leakage from your heater core into your chilled evaporator air. Common problem and I think You Tube can be a good guide for you here.

Rick

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Sorry, no matter how much information I put in these types of posts, I always leave something out: blend door actuator is the first thing I checked and it's operating correctly. I can cycle the air from the vents between "tepid/cool" and full hot. I had also removed the actuator and moved the door manually and could verify that it moves fully from stop-to-stop without anything blocking it. Unless the door cracked in half somehow or a piece fell off, I don't think it's an issue with the blend door. If there's another failure mode for the blend door other than the actuator, I haven't seen anything online...

 

You cannot accurately judge the freon level from pressure. I'm saying this as I'm sitting here using a 6k dollar ac recovery machine on a car. You need to pull the freon out and put the correct amount back in.

77 degrees outside with the car sitting in the garage all day and the engine bay cool versus sitting in the sun/being driven will yield very different resuts.

You have to pull it out and charge from fresh and measure the freon.

But, I can tell you that pressure is pretty low and it's very likely low on freon.

If you absolutely do not want to do that, put some freon in it until your high side is closer to 200 while in a shaded area and the low side is around 40-45. And the charge will not be right, but it will be.... righter

 

Fair point. Would you say if I'm going to get the system evacuated anyhow, it would make sense to also replace the accumulator and orifice tube while I've got it open? Would you also replace the condenser since it's cheap? Or would you just fully evacuate, do a full charge, and then go back to diagnosing?

And finally, any idea why the FSM would say those pressures are acceptable given the temp and humidity?

 

It's a generalized chart. It doesn't take cabin temp, condenser condition, evap condition, blend door function, radiator/condenser cooling fan condition or cooling fan speed (newer cars have at least 2 speed systems), interior fan speed setting, under hood/condenser temp etc into account. All those have considerable effects on pressure.

I was training one of our newer guys yesterday and I was showing him I could run the low side pressure up and down by 10 psi from just changing the fan speed in the cabin one to two settings, not even full speed to lowest speed.

You only need to replace the drier if the system has been open to atmosphere and moisture has gotten in. If the freon goes 100% empty atmosphere can get in. If it doesn't the freon pressure keeps it out.

You only need to replace the orfice if there's been a compressor failure that has sent debris through the system and clogged it.

Just draw the system down, measure what comes out, replace the service valves (super common to leak), pull a vacuum and fill it to the proper level.

I've done 3 ac services since we started this discussion lol.

 

It's a generalized chart. It doesn't take cabin temp, condenser condition, evap condition, blend door function, radiator/condenser cooling fan condition or cooling fan speed (newer cars have at least 2 speed systems), interior fan speed setting, under hood/condenser temp etc into account. All those have considerable effects on pressure.

I was training one of our newer guys yesterday and I was showing him I could run the low side pressure up and down by 10 psi from just changing the fan speed in the cabin one to two settings, not even full speed to lowest speed.

You only need to replace the drier if the system has been open to atmosphere and moisture has gotten in. If the freon goes 100% empty atmosphere can get in. If it doesn't the freon pressure keeps it out.

You only need to replace the orfice if there's been a compressor failure that has sent debris through the system and clogged it.

Just draw the system down, measure what comes out, replace the service valves (super common to leak), pull a vacuum and fill it to the proper level.

I've done 3 ac services since we started this discussion lol.

Thanks, I appreciate the advice! I'm a bit of a masochist (and also interested in this stuff), so want to try to tackle as much as possible on my own with this. I'm planning to take it to a shop to have them evacuate the system, but if possible I'd like to do the recharging myself. I had a few questions:

1. If I'm opening the system up to replace the schrader valves, does that momentary time of being open to atmosphere put the accumulator in danger of saturating, or would it be taken care of when drawing a vacuum for 1-hour before charging?
2. What do you recommend for refilling the PAG oil? I know the FSM has specific capacities for oil, but do you recommend just using R134a that already has the oil in it? Or would you measure out the correct amount separately? Or do things really need to be completely flushed and have a full oil charge reinjected?
3. Any other "gotchas" I should be considering here? Aside from the service valves, any other components I should replace while it's empty?

 

It's a generalized chart. It doesn't take cabin temp, condenser condition, evap condition, blend door function, radiator/condenser cooling fan condition or cooling fan speed (newer cars have at least 2 speed systems), interior fan speed setting, under hood/condenser temp etc into account. All those have considerable effects on pressure.

I was training one of our newer guys yesterday and I was showing him I could run the low side pressure up and down by 10 psi from just changing the fan speed in the cabin one to two settings, not even full speed to lowest speed.

You only need to replace the drier if the system has been open to atmosphere and moisture has gotten in. If the freon goes 100% empty atmosphere can get in. If it doesn't the freon pressure keeps it out.

You only need to replace the orfice if there's been a compressor failure that has sent debris through the system and clogged it.

Just draw the system down, measure what comes out, replace the service valves (super common to leak), pull a vacuum and fill it to the proper level.

I've done 3 ac services since we started this discussion lol.

Thanks, I appreciate the advice! I'm a bit of a masochist (and also interested in this stuff), so want to try to tackle as much as possible on my own with this. I'm planning to take it to a shop to have them evacuate the system, but if possible I'd like to do the recharging myself. I had a few questions:

1. If I'm opening the system up to replace the schrader valves, does that momentary time of being open to atmosphere put the accumulator in danger of saturating, or would it be taken care of when drawing a vacuum for 1-hour before charging?
2. What do you recommend for refilling the PAG oil? I know the FSM has specific capacities for oil, but do you recommend just using R134a that already has the oil in it? Or would you measure out the correct amount separately? Or do things really need to be completely flushed and have a full oil charge reinjected?
3. Any other "gotchas" I should be considering here? Aside from the service valves, any other components I should replace while it's empty?

No sir, if you open the system momentarily you're fine.

Do not use freon with oil, you'll put in too much and ac performance will suffer

YOU DO NOT NEED TO PUT IN OIL. You only add oil if there's been a loss of oil. And the only reason you would put a full charge of oil in it is if you replaced EVERYTHING AND all those things came with no oil. Some compressors come with an abundance of oil so that throws that whole deal off

I add dye to systems when I service them, that is mixed into an oil container on the machine, I put NO MORE than .4 ounces of oil per pound of freon capacity. If your system takes 1 pound I would do .3-.4 ounces for example... another example if your system takes around 2 pounds you probably have a total oil capacity of around 6-8 ounces or less sometimes. If you put too much oil even a little ac performance suffers. So be cautious on the oil.

when I do ac services in the driveway I get the cans and do my best to measure it by hand.

If you get the basic cans of freon USE ONLY FREON, not the ones with sealers and gimmicky this and that, they come with .75 lbs in them. If your system takes 1.5 pounds you use all of 2 cans. If it takes 2.25 that's 3, if it takes 1.8 or so that's 2 and about 1/2 of a can. Shake the can repeatedly as you fill the system to gauge the weight of the can. Or use an actual scale to measure the weight.

 

I heard some say to put it up to 45 to 50 try another can of freon like half to raise pressure slowly to see if helps that air pressure is pretty low