How to Test Evaporator 4 Leaks? - Team Camaro Tech
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post #1 of 3 (permalink) Old Jun 29th, 10, 08:38 PM Thread Starter
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How to Test Evaporator 4 Leaks?

I am trying to put an all original a/c unit back together on a 67 Camaro. The only thing left under the hood is the suit case with the evaporator inside, the POA is still attached along with the expansion valve. I want to test each component before I proceed with buying & connecting the other missing parts. I am planning on converting the system over to R-134. I have been reading & researching everything from this site & others concerning specific issues. I cant find any information about testing the evaporator, either with pressure or vacuum.

Is there a way to test the evaporator for leaks, malfunction, etc. before going on to other issues? Thanks
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post #2 of 3 (permalink) Old Jun 30th, 10, 03:19 AM
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Re: How to Test Evaporator 4 Leaks?

You can hose the two ends together and place a gauge, one to read at least 150 PSI, and a 1/4 inch threaded fitting for the gauge manifold and pressurize with nitrogen to 100 PSI. Snoop all the joints for leakage, fix them, then leave it overnight and check later the gauge has not fallen.

Or your A/C person take a look and let them test it for a cookout in return.

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post #3 of 3 (permalink) Old Jun 30th, 10, 05:21 AM
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Re: How to Test Evaporator 4 Leaks?

For R-134a conversion, you are going to want to remove the POA valve and look into the big end (discharge side) where you will find the 7/32 nut with a hole. Turn the nut CCW 1/4 to 1/2 to lower the evaporator pressure from 29 to 27 inches.

This change coupled with new barrier hoses, receiver/dryer, green o-rings, a R-134a compatible compressor (or a converted A-6), a parallel condenser and about 2.5 lbs of R-134a should do it.

Try to get all the old mineral oil out of the evaporator (flush). Also check the filter screen on the expansion valve for trash.

You didn't specify, but I would crack open the suitcase and clean out the 40+ years of accumulated mung between the fins of your evaporator.

If you want first hand advice on your evaporator, call the guys at Classic Auto Air.
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