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New System - Not cold - where did my gas go

themcguire on Sat August 17, 2013 3:15 PM User is offline

Year: 1988
Make: Chevrolet
Model: Blazer - Full Size
Engine Size: 5.7l
Refrigerant Type: R134a
Ambient Temp: 84
Pressure Low: -25
Pressure High: -10
Country of Origin: United States

I just rebuilt this system to convert to R134a. Following is NEW:

Parallel Flow Condenser
Orifice Tube
Accumulator / Drier

I flushed out the evaporator and hoses using a pressurized can of flush. Then blew them out till dry with compressed air.

I put 8 oz. of ester oil into the compressor and then rotated the compressor 10 times to circulate the oil in the system.

I vacuumed the system till the blue gauge reading was -40.

With engine running and a/c on max I started to put in R134a. My system was R12 and it took 52 oz of R12. So going with the 80% rule I put in exactly 42 oz of r134a. (3 full 12 oz cans, then 1/2 can. Used a scale to monitor the weight on the last can)

It took forever - like 15 min per can - compressor clutch NEVER engaged. So after all was in I jumped the switch at the drier with a paper clip to for the compressor to engage.

Compressor comes on. But DOES NOT GET COLD and my readings are -25 on low and -10 on high side.

Where did my gas go ?

Any ideas what I did wrong or what is going on ???????? Help

Dougflas on Sat August 17, 2013 3:31 PM User is offline

I have never seen a low side (blue) guage read -40. From your readings, you have a restriction. High side is in a vacuum at -10. Low side is in vacuum also. Did you remove the shipping plugs from your new parts????

themcguire on Sat August 17, 2013 3:39 PM User is offline

Come on your teasing me right ? I had to remove the plugs to connect the system together. 2 plugs from the new condenser, 2 from the drier, one that covered both ports on the compressor to put the oil in.

The drier was for a R12 system so I had to put an adapter on it for the R134a. Was I supposed to remove the schraeder valve before I put the adapter on ? Could that be where my gas leaked from ?

Jag987 on Sat August 17, 2013 4:15 PM User is offline

I think it was a valid question. I have seen some parts come with two plugs, one that goes over the connection threads and the actual seal that fits inside the new part. I have never seen a low side gauge that even shows -40 so I have to wonder some about that. If it took 15 minutes to charge one 12 ounce can, I would have stopped right then to figure out what was going on. Sorry, I don't have any ideas right off.

I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

themcguire on Sat August 17, 2013 4:25 PM User is offline

I have been reading while waiting the hear from you. In one article he points out that you must remove the schrader valve from the drier before putting the adapter on. I did NOT do that. But since the adapter had loctight on it is it safe to remove the adapter, apply new loc-tight and the schrader from the drier and then reinstall it ?

Does this mean that all I did was vacuum the hose omg lol

I removed the adapter and then removed the schrader valve. Installed red loc-tight and reinstalled the adapter.

Vacuuming again now

No gas came out when I removed the schrader on the drier so I must have lost all of it.

Sorry Earth, It was a mistake. Forgive me?

Edited: Sat August 17, 2013 at 5:03 PM by themcguire

mk378 on Sat August 17, 2013 7:28 PM User is offline

You can tell if you're actually coupled to the car and evacuating the whole system by opening only the high side valve wheel on the manifold when you start to evacuate. Seeing the low side gauge go negative demonstrates that the vacuum is being drawn through the car lines. (If it stays at zero you're just pulling on the hose.) Then open both valves fully to get all the air out.

Seems there's a BIG leak somewhere. Like an o-ring left out or a hole corroded through something. Do a static pressure test, just put in a few psi with the engine off and see if it goes down by itself. Listen for any hissing from leaks. Don't run the compressor until you have a couple of cans charged statically. It should not be necessary to jump the switch.

Adapter with its own shrader valve should have the original shrader removed for better flow in and out. This is not absolutely essential though (at least with straight on adapters) since the adapter has a pin to push down the original shrader when the new one is pressed. Right-angle adapters will not work without removing the original shrader.

Report pressures in psi, not the temperature scale.

Edited: Sun August 18, 2013 at 10:23 AM by mk378

Jag987 on Sat August 17, 2013 11:54 PM User is offline

The temp scale!!! Now those numbers almost make sense!!!

I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

Leggie on Wed August 21, 2013 12:17 AM User is offline

If you have a leak that big, you would hear it hissing or smell(faint sweet smell) the refrigerant. If you can't build enough pressure in the system to close the low pressure cut out switch, that is when you stop.

You bypassed the system by tricking the system to think there is refrigerant in it when its empty and this can be damaging to the compressor.

Static pressure test is better done with dry nitrogen. Refrigerant will change in pressure as it dissolves into the oil and appear as if its leaking even when it isn't.

Edited: Wed August 21, 2013 at 12:21 AM by Leggie

Dougflas on Wed August 21, 2013 5:04 PM User is offline

No, this innocent face would not tease you. I had a drier come in that had plugs in them that had a tab you had to grip with pliers to remove. Then there were caps on the threads. I almost did not notice the plugs.

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