If it isn't leaking, what are the other fail points? Compressor internals? Bill said he filled it after the repair and it stopped blowing cold air after 16 miles. Sniffer should have picked up any leaks.
Advice on AC leak 1967 Coronet
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If the compressor is not pumping down, it could be the valves OR what refrigerant was used? If R-134A, was the evaporator pressure regulator (EPR valve) located in the inlet of the compressor, REMOVED? Just asking.....
BOB RENTON
gtx6970
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I pressure ckd the evap while it was apart.
Back together it held nearly 30inches vacuum for nearly an hour ( I did not pressure ck the remainder of the system. But sounds the Current owner has )
My comment was only that the evap was pressure ckd at almost 3 times normal operating pressures Only due to the fact it was such a pain to replace if needed once back together.
With that quick of a loss, and that much dye in the system, the Evap drain would show signs of dye. Nor would it hold a vacuum for that length of time if the evap leaked that fast .
Not to mention there would be an odor inside the car IMO only.
The car had already been converted to r134a when I bought it. And I do not know if the EPR valve is in it , or not. ( But my gut says its not )
I have not seen the car in person since these issues surfaced so I cant say what is or isnt the issue unless I look it over in person
But IMO would be looking really hard at the condensor or compressor nose seal
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Pressure check the whole system with Nitrogen at 300 pounds, that will show any weak point and leaks.
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As I noted, the CONDENSER operates at +250 PSI @ 70 MPH @ 110° F day. The shaft seal is a simple csrbon vs ceramic cartridge assembly (unbalanced hydraulic design). The system high pressure relief valve (HPRV) is normally set @ 1.5x max NORMAL working pressure. It could be seeping/weeping. IF the compressor has internal leakage (BAD VALVES) a lack of cooling would result; internal leaks would not be visualized. YES......pressure test with DRY nitrogen or the dryer will become saturated. My bet is the CONDENSER IS AT FAULT.......
BOB RENTON
Interesting find today. As I was doing my normal piddling around in the garage wiping down engine bays with Simple Green I noticed the Pressure Switch on the Dryer was loose. Really loose!
Used the socket (oil sender socket fit perfectly) and the switch was almost two full turns loose!
Not sure this is the leak? Switch had no dye, oil, or any evidence of leaks, but it definitely was loose! Measured open circuit on the switch so I know my recent charge of refrigerant is long gone. Not sure I am going to spend another $40 on a charge, but maybe I'll be talked into it.
Used the socket (oil sender socket fit perfectly) and the switch was almost two full turns loose!
Not sure this is the leak? Switch had no dye, oil, or any evidence of leaks, but it definitely was loose! Measured open circuit on the switch so I know my recent charge of refrigerant is long gone. Not sure I am going to spend another $40 on a charge, but maybe I'll be talked into it.
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IMO.....usually, there is a small O-ring that seals the pressure switch to the male thread it fits over. This could be the source of your leak. The switch is EITHER the pressure cycling control or the minimum pressure switch. The O-ring is the seal....don't over tighten. You could pull a vacuum on the system or pressurize with nitrogen to leak check b4 recharging......
BOB RENTON
gtx6970
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pull a vacuum on it and let it sit all day. See where / if it drops to
Some Car Guy
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Find a shop with the nitrogen tester. I just had my car charged up and the guy let me hang around while it was being done. He described how that made everything simple to leak test. Luckily my work held and nothing else was busted so I didn’t get to see it in action. He’d just done a truck with a busted Evap that was found using nitrogen.
Lefty71
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Ac systems dont really hold much refrigerant to begin with. If you ever heard a "hiss" the charge would be gone in 5 minutes and no test would ever pass. You found a leak with the dye.... I'd go right back there for an answer. What did the o-ring look like? You should have studied it with a magnifying glass if need be. Was it ripped, deformed in any way? The fitting halves should have been studied the same way. Regarding the dye.... once it's in, it's in....you don't need to re-up any further. Leaks with dye will only show if the oil gets to the area in sufficient quantity to seep oil out. Sometimes it just doesn't happen. In your case, the hose could well be the problem. Are you using R12 or R134a?? When they first changed over years ago, we were told that the old R12 hoses were not likely to hold R134a and may need changed out.
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The O Ring was not the problem.
I paid a professional to charge the system with Nitrogen and Dye. The charge leaked out in a few days. No sign of dye. He wants to change the compressor seal first as they are so prone to leaking.
I paid a professional to charge the system with Nitrogen and Dye. The charge leaked out in a few days. No sign of dye. He wants to change the compressor seal first as they are so prone to leaking.
gtx6970
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Most.of the time .
To find a nose seal leak you have to pull the clutch and coil off to find it.
Another way is with a UV light and the associated glasses .
Pull the condenser loose and look down the back side with said UV light
To find a nose seal leak you have to pull the clutch and coil off to find it.
Another way is with a UV light and the associated glasses .
Pull the condenser loose and look down the back side with said UV light
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The "nose seal" aka the compressor's mechanical shaft seal, is a simple cartridge type device....the ceramic half is the stationary part, sealed to the housing with an O-ring and the rotary half is sealed to the compressor shaft with a 2nd O-ring. The compressor clutch must be removed in addition to the clutch coil b4 getting access to the mechanical shaft seal assembly. The refrigerant must be removed b4 attempting to replace the mechanical seal as it has refrigerant pressure in the compressor's crankcase. This would be an excellent time to check the compressor's oil level.....refer to the FSM...for the methodology.....assuming it's the RV-2 compressor. The mechanical seal assembly is very simple but very FRAGILE.....do not bump, pound or force the new seal assembly in place. Also a good time to inspect / replace the rotating clutch bearing....may have caused the mechanical seal faces to get out of alignment and leak both refrigerant and refrigerant oil. You'll see refrigerant oil stains or tracks on the magnetic clutch faces, between the rotating face and stationary face. Just my thoughts......
BOB RENTON l
With dye induced into the system, wait until it’s dark outside, turn off all lighting and take your black light and go over every inch of hose, condenser, and compressor. You might be surprised at what you find.
Demonic
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Hopefully you found it. I've always been amazed that the auto industry does NOT adopt commercial refrigeration leak test methods and mind set. I work on small systems that take 50 lbs of 410a to chillers that take over 2000 lbs of 134a. We make the units leak free and verify them so with 300 psi nitrogen, and time - hold that pressure for days if need be.
Lots of good advice in the previous replies above. Lets face it, most of our cars are a hobby, luxury, and not like your house where you're keeping the wife & kids/family/yourself cool. Take your time, make it leak-free.
I will strongly discourage using compressed air. I realize there is a huge gulf between using nitrogen at commercial test pressures -say 180 minimum to 325 or so max - which not many have access to, vs compressed air; which many hobbyists have. Air compressor air is full of moisture, and nitrogen is not. The inside of an HVAC system wants to be cleaner and dryer that a hand assembled Hemi.
The desiccant in a filter-dryer will start pulling humidity out of the air it is exposed to as soon as you remove the caps, as Mr Renton mentioned. Likewise an empty system if it is assembled days before charging. A good vacuum can slowly pull it out, but it can take hours and hours.
Off my soapbox. Sorry for the rant.
Lots of good advice in the previous replies above. Lets face it, most of our cars are a hobby, luxury, and not like your house where you're keeping the wife & kids/family/yourself cool. Take your time, make it leak-free.
I will strongly discourage using compressed air. I realize there is a huge gulf between using nitrogen at commercial test pressures -say 180 minimum to 325 or so max - which not many have access to, vs compressed air; which many hobbyists have. Air compressor air is full of moisture, and nitrogen is not. The inside of an HVAC system wants to be cleaner and dryer that a hand assembled Hemi.
The desiccant in a filter-dryer will start pulling humidity out of the air it is exposed to as soon as you remove the caps, as Mr Renton mentioned. Likewise an empty system if it is assembled days before charging. A good vacuum can slowly pull it out, but it can take hours and hours.
Off my soapbox. Sorry for the rant.
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An additional aspect is AIR, in a refrigerant system, is considered a NON-CONDENSIBLE, and must be purged or removed b4 recharging. YES....air contains MOISTURE, which will saturate the desicant in the receiver/dryer and can form acids which, over time, can damage/corrode components. YES.....vacuum the system, for several hours, to insure moisture removal.......
BOB RENTON
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