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Advice on AC leak 1967 Coronet

Billccm

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Hello: I have a 1967 Coronet that has an AC leak. I put a can of DYE in the system and found it sort of sprayed downward under the area circled in the photo. Hard to tell if it leaked at the fitting or crimp. Not sure what to do next here. Appreciate any advice. Thanks.

ac_leak.png
 
More than likely the O ring. Discharge the system and replace. Then check again. Hopefully you have a recovery machine and can pull a vacuum, before recharging the system. Freon is quite expensive now-a-days.
 
Take that fitting apart and look at the o-ring, you may see a problem with it.

Might just replace ALL the o-rings in the system.
 
Take that fitting apart and look at the o-ring, you may see a problem with it.

Might just replace ALL the o-rings in the system.
Good idea while the system is down.
 
Do all of them. I got a kit that had several of each size, plus the oil to put on them. I found two black o rings, one of which was disintegrated. And one hose had no o ring at all.
 
Make sure to use the proper oil and o-rings compatible with the type of refrigerant you are using. R-12 was the original and domestic production outlawed many years ago. Very expensive if you can find virgin Freon®.
The newer refrigerant ( also being discontinued) used on most cars in the last 30 + years is R-134A . It used different oil, seals, hoses and recharge fitting adapters ( bigger sized so you can't mix refrigerant.)
Some use the old original hoses if they don't leak.
System needs to be evacuated and placed under vacuum for at least 1/2 hour.
This will detect any leaks in the system as well as remove any moisture in the system.
If the system has been open to the atmosphere for any long period of time, the drier must be replaced as well. I would also replace the schrader valves. Very inexpensive and forgotten by most people.
Best done by an a/c professional.
 
I'll spare you several long stories, but two of my friends (one just retired as a mechanic and the other is a longtime A BODY guru) are stumped. Here is what has been done (some items have been done twice):
1) The O RING was replaced.
2) Dry compressed air was charged into the LOW and HIGH sides. About 120psi. We listened and heard no hiss. Sprayed soapy water on all fittings and saw no bubbles. Left the compressed air charged for about 45 minutes and no leak down.
3) Ran a vacuum on the LOW and HIGH sides to about 22 inches. Decided to leave it for awhile and have lunch. Came back almost two hours later and the vacuum held. My friend commented that this was a great AC system and we should charge it!
4) Three cans of R134. High side pressure was 220psi. Vents blowing 41F air.
Drive the car 16 miles and really enjoyed the ride. Never had a B Body with AC and was so happy. I could really get used to this!
On the way home compressor stops as the low pressure switch is open.
Three cans of DYE have been put into this system, and the black light shows nothing. Fittings are dry.
I'm done. Either Vintage AC or the car goes on the block!
Thanks for the replies.
 
I couldn't find where the dye was coming from on mine for almost a month.

Finally found it was coming from right in between the connector prongs on the pressure relief valve mounted on the dryer.

It all vented straight out the grill.

Only 2-3 very small droplets way down on the inside of the valence (that I only noticed afterwards) and a pin head sized stain right between those prongs.
 
3 cans is going somewhere. Might need to check the evaporator as Jerry alluded to above. Getting in there sucks for sure.
 
If I pull this heater box it's not going back in. Vintage air will be the fix.
 
Yikes! Their prices have gone way up. $1995 for a complete system. I swear is was $1400ish last time I looked.
 
I'm leaning towards evaporator myself. My A Body friend says he's never seen one go bad as the Mopar design is very robust. You'd think 100psi would have been leaking and hissing away in that heater box.
 
Being involved in HVAC for almost 50 years, I can GUARANTEE they can leak. See attached pics showing holes (leaks) found in 2 tube bends. This was from a 73: Challenger I once owned.
Ron
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IMO if freon leaks out in 20-30 minutes no way in hell will the evap will hold vacuum for 30 minutes and / or not show some signs of dye in the condensation drain.
 
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IMO if freon leaks out in 20-30 minutes now way in hell will the evap will hold vacuum for 30 minutes and / or not show some signs of dye in the condensation drain.
The "U" shaped return bends are almost, if not impossible, to successfully repair, due to being so thin from forming and swaging, even if using Heli-arc. IMO.... your long term success will likely be to replace the coil assembly. Another possible leak point is the compressor crankshaft shaft seal.....a simple carbon vs ceramic cartridge assembly; its subject to failure due to radial shock loads when the magnetic clutch engages at high RPM......
BOB RENTON
 
The "U" shaped return bends are almost, if not impossible, to successfully repair, due to being so thin from forming and swaging, even if using Heli-arc. IMO.... your long term success will likely be to replace the coil assembly. Another possible leak point is the compressor crankshaft shaft seal.....a simple carbon vs ceramic cartridge assembly; its subject to failure due to radial shock loads when the magnetic clutch engages at high RPM......
BOB RENTON
I understand that.

But if it looses charge that fast. There is signs somewhere .

And imo. The evap condensation drain will / should show some signs of dye .

This my former car.

I had the box apart to replace heater core.
I pressure tested to evap core with 125psi line pressure and submerged it in water.

No signs of a leak anywhere.

Not saying it's not the cause .

But I have serious doubts it's the evap

Again. IMO only
 
I understand that.

But if it looses charge that fast. There is signs somewhere .

And imo. The evap condensation drain will / should show some signs of dye .

This my former car.

I had the box apart to replace heater core.
I pressure tested to evap core with 125psi line pressure and submerged it in water.

No signs of a leak anywhere.

Not saying it's not the cause .

But I have serious doubts it's the evap

Again. IMO only
Since you've pressure tested to 125 # without leaks, have you pressure tested the condenser as its subject to higher pressures? How about the remaining tubing, connections, dryer, pressures switch. Since you've added dye, the leak SHOULD BE EVIDENT. The condenser is subject to road debris and it's hi operating pressures......just saying.....
BOB RENTON
 
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