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I might have a A/c leak in the evaporator....i'm hoping it's the compressor instead. got 38 degrees with my new vintage air condensor and spal fan, then it all leaked out somewhere!!Anyone know if you "Must" remove the "whole dash" to get the evaporator out or can you just remove the lower gauge panel assembly on a 74 car? Confused
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Emery,

Tear down is a lot of work to find the problem wasn't with the Evaporator.

I'm a novice on A/C, but my first instinct would be to perform some kind of leak test on the evaporator side of the system. With a little searching you should be able to find fittings to blank off the return hose and connect an air line and pressure gauge to the other. If there is a pressure drop over time then there is a leak in that side of the system and you can tear down more confidently.

Julian
The easiest way to to pressure test with nitrogen, you will hear the leak. We use Nitrogen so no contaminents are introduced. You can use a sniffer but could get expensive trying to keep refilling with R134 and here in NY if you get caught releasing it in the air well out come the angle bracelets.. LOL

If you tested everything else .. do the dirty deed becuase Hawaii is HOT and I would not want to be in a pantera in that heat. Last year I went to Conn to the Concourse De Eligance and with no AC it was HOT in that car.

Ron
Jack DeRyke claims to have removed the fans without removing the dash but I don't see any way to remove the evaporator without removing the dash. Once you have removed the console the dash isn't much more work to pull any way and it sure will be easier. There is are studs and nuts on the very top that would be near impossible to get to without pulling the dash.
Forest
quote:
Jack DeRyke claims to have removed the fans without removing the dash



Emery,

Oh drat, Forest is remembering, better than me, the article I had in mind. Jack did say he could get the fans out, not the evaporator. Others who have suggested sniffers or nitrogen are the way to go unless you KNOW the leak is in the evap.

And if you converted to 134 and kept your old r12 hoses, you are likely leaking the smaller molecule 134 out the walls of the non-barrier r12 hose.

Larry
Emery, BD,

R134a is not compatible with the mineral oil lubricant or the viton / buna-N elastomers (o-rings, seals, compressor parts, hoses) that were used in your R12 a/c system. And the heat absorbtion properties of R134a are different from those of R12. So a properly done conversion will flush all the mineral oil from the entire system, replace the receiver-dryer, expansion valve, compressor, any rubber hoses and all the o-rings and refill with the correct poly alkaline glycol lubricant. Replacement R134a specific service fittings are screwed on at the service ports & a big R134a decal is attached near the service ports as well.

The R134a has probably chewed away at an old o-ring or a thin spot in an old hose.

I search for leaks by purging the system & pressurizing it with air (Ron uses N2 which is better because it is dryer). No need to blank off anything, just apply pressurized air to one of the service ports & pressurize the entire system to about 100 psi. Then I apply a liquid specifically designed to locate gas leaks in tubing systems (Snoop, sold by the Swagelock Company) at all the fittings, connections, etc. It creates bubbles where the leak is located.

Often Snoop applied to a fully charged, non operating system will be enough to find the leak. Fully charged, a non operating R12 system develops about a 70 psi pressure throughout the closed loop system. I'm not sure about R134a.

An a/c shop will have an electronic monitor that detects halogen gases, a detector like that is often successful at closing in on the location of a leak. I would think it would be money well spent to let an a/c shop locate the leak, rather than tearing apart your car needlessly.

your friend on the DTBB
Last edited by George P
George - Thanks for the reply. I was going to replace all of my hoses with new hoses but two of them are running through the right side rocker panel. I know that some guys run the hoses through the center counsil. I have looked up in there and it doesn't look like there is enough room to get the two hoses through. To run the hose through the rocker panel I would need to cut the panel off to replace the hoses. The car has already been repainted. I have a new compressor, receiver-dryerand expansion valve plus the system has been flushed. I guess I will struggle with this by trying to patch it here and there.
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