AC Not Working

[Burning oil]

Take War Wags advice about the VOV. It made a huge difference. I also put a 1.5 " thick condinser (I think for a Suburban) on it. This is the best/cooldest A/C Ive ever had on these body style trucks.
I made a stop last Friday and it was very hot outside, left it running just a couple minutes with the air on. When I got back in the seats were even cold, felt so good!!

 

[Big T]

Ok I'm going to do this right. I will get the vac thingy and gauges from Harbor Freight (aka made in good old China at the cost of a bowl of rice and a gun to their back.....Dead Kennedys). Do I drain the system of 134a that I've already put in and start anew? Just where in the heck does this VOV go?

 

[Burning oil]

Ok I'm going to do this right. I will get the vac thingy and gauges from Harbor Freight (aka made in good old China at the cost of a bowl of rice and a gun to their back.....Dead Kennedys). Do I drain the system of 134a that I've already put in and start anew? Just where in the heck does this VOV go?

The system should be empty. I would even flush it out and blow air through to help dry it out of flush. Get a new dryer. VOV go's in the same spot as orfice tube in the condenser. You can use air to blow out/remove the old one.
8 oz of new oil maybe more for a Suburban?? I got the $70 electric vac pump from Harbor fake. worked good its first time.

 

[Big T]

What and where is the dryer?

Is the condensor the radiator in front of the engine rad?

How do you flush the system? Are there tools or equipment needed to do this?

Where is the oil added?

Again, I am a complete neophyte on ac. Crank position sensors I am now an expert, but not so with ac.

 

[94blazer]

What and where is the dryer?

The Dryer/accumulator is the silver cylinder on the firewall at the passengers side. Should be a line into it, out of it through the firewall, and the low pressure switch is installed there.

Is the condensor the radiator in front of the engine rad?

Yes.

How do you flush the system? Are there tools or equipment needed to do this?

An air compressor, Blow gun, and a bottle of flush or just isopropyl alcohol.

Where is the oil added?

I usually dump the oil out of the dryer into a cup to measure, and add it back in the dryer. Same with the compressor.

Again, I am a complete neophyte on ac. Crank position sensors I am now an expert, but not so with ac.

Your not really asking for a dissertation on how and why the AC works are you?

 

[Acesneights1]

The principles of A/C are really really simple. Think of it this way..Ever bust the air fitting off a tank full of compressed air ? What happens ? It gets frost on it and cold. Same thing with an refrigeration system The compressor compresses the refrigerant gas at the Orifice(GM Ford etc etc) or Expansion valve( I like better, more seen in HD applications or older systems.) . The orifice is basically just a small tube restrriction. ON the pressure side it's hot. ON the other side of it it becomes cold as the pressure is released. The hot side or high side is run throgh the condensor(radiator looking thingy in front of the radiator) for additinal cooling. The accumulator dryer is sometimes reffered to as a filter but it really isn't . it's filled with moisutre absorbing beads that ..absorb any moisture. It consequently somewhat acts as a filter but that is not it's primary purpose. Moisture in the system=bad. How hard the compressor runs and how much cold it makes is determine by different factors depending on what kind of system you are working on. Low pressure switch controls it on GM, newer ford and I think Dodge but I don't really work on light duty stuff except for favors or my own. I specialize in Heavy trucks and Heavy equipment. way more money to be made and much easier to work on.. ON an Expansion valve system the valve is regulated by the temp at the evaporator(The hearter core lookin thingy in the blower box in the cab). It has a small caplillary line that is usually clamped to the low side line of the evap or stuck right in the fins. Many many Macks had issues with the tube falling out of the evap core and causing the system to constantly cool to the point of feeze up and damage. Some think R134a doesn't work as good as R12. I dispute that doing many conversions. What I have found is older systems with 8 cfm or larger compressors had no issues at all. 6 cfm or less didn't get quite as cold at idle. warwagon has mentioned the Variable orifice which I personally have never seen but will check out next one I do to rectify this. 90% of the stuff I have worked on has expansion valves so that would not work. I probably oversimplified this but that was the idea.

 

[Acesneights1]

Here's a really bad sketch. I'm no artist. What I drew shows the drier on the high side. GM it's on the low side.

 

[merlinhenry]

Most air conditioner will not blow as cold of air because there is less air going over the condenser, causing higher head pressure, and therefore higher suction/low side pressure. When the Suction pressure goes up cooling efficiency goes down so this makes sense at idle.Backflow the heater core and change your coolant.