My A/C was not blowing cold, so I decided to investigate. I rented a set of gauges and checked the pressures. Pressures showed a bit low compared with the table from the FSM. I went to charge the system with refrigerant, when the can tap broke...completely depressurizing the system! Since the A/C compressor would no longer turn on due to low pressure, I disconnected the battery to try to reset (with no luck). I headed back to the auto parts store and rented the vacuum pump. I pulled a vacuum on the system, checked an hour later, and didn't lose any pressure. I ran the vacuum pump for 45 minutes more to evacuate the system, then attempted to add refrigerant. I turned the car on, but the A/C compressor still wouldn't turn on due to low pressure. I added about 1/2 of a can of refrigerant, and finally got the compressor to turn on. I turned the fan up and the temp down all the way. I shook the can as directed, moved it to different locations on and next to the car, but couldn't get the car to take more than 1/2 of a can. After running the car for about 45 minutes, I shut the valves and disconnected everything for the night. Pressures are still low, and the car is blowing hot air from the center vent. Ambient temperature in the garage is very close to the climate control display, and humidity is below 20% (so technically I'm "off the chart" but not by much!) Got any ideas why the pressures are so low, but the car won't take more refrigerant?

 

Are you sure the compressor is running? It sounds like the system took what an empty system will take without the compressor running.
The low pressure cutoff switch often needs to be jumpered to close the circuit and allow the compressor to run until there's enough refrigerant drawn in to keep that switch closed on its own.

Another thing you can do is put the refrigerant can in some very hot water, that will increase its pressure and force more refrigerant into a static (not running) system.

 

You're absolutely right. I removed the ac clutch relay and threw in a jumper. After that, it charged right up. Thanks for the second opinion!

 

Another thing you can do, though it's not recommended, is to turn the can upside down. This will empty the can. Just don't do it all at once, or you can damage the compressor. BUT-If you do turn the can upside down, push the button on the can for only 2 or 3 seconds, then release it. Wait 4 or 5 seconds, then push down again for 2-3 seconds. This should protect the compressor from trying to compress liquid refrigerant, which we know won't compress!! I've tried leaving the can between my header pipes for a few minutes, even put them in the Sun. Holding the can upside down has worked well for me......

 

Thanks for the tip!
I was shaking the can as recommended (every 2-3 seconds, 90 degrees of rotation, etc) until it was taking too long. Then I inverted it, but only for a second or so at a time. Hot water helped. I was hesitant to rest the can near the engine, so I kept it near the passenger side front tire where there was plenty of hot air exhausting.

 

I am a bit perplexed on your difficulty in getting refrigerant into your system. If you are charging your system on a 70 or 80 degree day, your r134a cans will be around 75psi. If your system is running, it will be around 35psi.

Others may have different experience but I have never had to heat a can of r134a. Starting with an evacuated system has been enough to get a sufficient amount of r134a into the system to allow the compressor to run. Low side system pressure is then enough to always pull in the rest of the charge. Pulling primarily gas (can upright) will take longer than can at 3 or 6 oclock. Personally, I have no concerns with pulling in liquid from the can. I was an engineer working on the launch of this Delphi compressor and we subjected them to a heck of a lot of liquid pumping abuse during design verification testing. So in my case, I let it pull in liquid refrigerant through my charge hose and fittings.

 

I had never heated a can of R-134a before this either, but it definitely helped it go faster. I just used hot water from the tap, not boiling. I feel like every time I've added refrigerant to a car, it always takes longer than expected. I'm glad the compressor is stout!

 

Question...I am experiencing the same thing. Hot air coming out; bought a recharge can and it was showing low 30's on the low side. I started to fill the system, got it to high 40's and it was blowing much colder air. I parked the car for about 1.5 hrs and went to get dinner and it's blow hot AF now.

Got it back home, compressor is running, no funny noises, put the gauge back on the low side and now it's reading in the red/waaaaaay above 50.

Thoughts? How did you do this ac clutch relay jumper?

I would like to drive this thing this summer and seeing as I live in Texas, A/C is a must. I can't confirm if the ac was ever blowing super cold like it is supposed to. Just got the car in December and we always roll with the windows down.

 

Here's how I jumpered the A/C clutch relay:

Did you buy a recharge can with a gauge attached? Did you use gauges as seen in the photo above? What is the high side pressure?

It sounds like you have a leak in the system if it blew cold after a charge but then blew hot after sitting.

 

Excellent video! I just pulled the #27 fuse to also let the vents reset; I have a dumbass Optima red top and after installing my Tick MC the battery died from having the door open, so I am trying things one at a time.

I bought a recharge can but it only has the single low side gauge on it. I *think* my buddy may have a dual gauge setup I can borrow if these two tricks don't fix it. I would LOVE to have 40 degree air blowing from these vents!

 

Just in case your buddy doesn't have them, your local Autozone will rent the gauges, (also the leak detection kit and vacuum pump if you need them) with a deposit on your credit card.

 

Perfect! Thanks for the quick reply my man. Hopefully I can get this sorted out quickly and get back to enjoying the car.

 

Try taking out the spork tube and put a new one, they only cost 15 bucks. But they get blocked if you put freeon in that has a sealing additives. I would try that next

 

Got the gauges/pump this am. Maaaaan. The lowside reading PEGGED the meter. Highside was 150. VERY high and low based on the charts for 85*.

*UPDATE* the vac fitting wasn't tight. Fixed that and it is holding 30 on the vac. I have about 30 minutes before I have to head out for the day so I'm going to let it keep doing it's thing and then work on the recharge after work tonight.

 

So I did a 60 minute vacuum of the system. Jumpered the low side and it still will not take more than half a SMALL can of R134a. When I put the dual gauges on it the low side reads 45, the high side is also reading 50. That is with the system on full blast, jumped to close the circuit, doors open and it's 90* out. (Damn Texas mornings!) After the 1/2 can the LOW side is reading high; like 100+ high and the high side is still at 50.

I was am using the recharge cans from Oreillys and I cannot get the dual gauge set (with third yellow line) to pull the R134A out of the can. I have to use the little ghetto gauge/trigger to get it into the system and then it's not cycling and showing the above numbers.

I am completely perplexed here. #Help

 

Did the system hold vacuum after you disconnected the pump?

I wonder if you have a restriction in the system, like a clogged orifice tube.

 

Yes sir. Held 30 (that's all the gauge has on it) for 60 minutes.

 

Well, well, well...this is a bit embarrassing (the condition of this thing) but VetteMed thanks for the hot tip! Hopefully this is the last road block.

 

OOF. Ok, so, now you need to flush the whole system thoroughly. Maybe even consider a new condenser, since that's easy enough to change and somewhat difficult to thoroughly flush. It's likely your compressor is dying, that's where all that black stuff comes from, so I'd replace that too, unless you want to do all this again in a few months.

 

With a known working compressor and a stopped up orifice tube, you'll get higher than normal high side pressures and lower than normal low side pressures. The most common thing that will stop up an orifice tube is failing compressor and/or overuse of stop-leaks. I've also heard of failed accumulators causing orifice tube blockage, but this would be rarer. From the looks of your orifice tube, your compressor is probably failing. Condensers are practically impossible to flush clean, you can get a new one for probably less than $100. Also, should replace the accumulator/dryer. Once everything back together, vacuum as long as you can stand it and at least one hour, then check to confirm the system holds the vacuum. Any moisture in the system will eventually boil out under close to a perfect vacuum and the goal is to get it moisture-free. Research how much refrigerant oil to put back in the system based on what all parts you replace. Don't rely on gauge pressures for refilling refrigerant, look up how many ounces of R134a are required and refill as close as you can to that specification. R134a systems are particularly sensitive to underfilling and overfilling of refrigerant.