AC Guru's, I need some help.

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zakimodo

zakimodo

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Sorry Not an old Mopar.... but a newer one.

This is a 2010 Dodge Avenger (RT 3.5l)

This spring my wife noted that the AC in her car wasn't working. I checked the system and found it was low on charge (just enough to not override the pressure switch). I recharged it and all was well. 3 weeks later it was low again just like before. I decided to recharge with some dye this time in hopes of finding a leak.

2 weeks later (yesterday) there was little to no refrigerant left. I borrowed an AC sniffer/ UV light from a friend and found that the connections at the condenser were leaking. I replaced the seals last night, pulled a vacuum on the system for about 40 minutes (pulled down to 28inches). I let it sit another 30 minutes with the valves closed and the pump off and saw that the gauge had not moved. I went ahead and charged the system.

Today, my wife gets in the car and the AC won't work. Haven't got to check yet, but I am assuming its low.

What am I missing? With the vacuum test turning out as good as it did I can't understand how it would leak down so quickly.
 
zakimodo said:
Sorry Not an old Mopar.... but a newer one.

This is a 2010 Dodge Avenger (RT 3.5l)

This spring my wife noted that the AC in her car wasn't working. I checked the system and found it was low on charge (just enough to not override the pressure switch). I recharged it and all was well. 3 weeks later it was low again just like before. I decided to recharge with some dye this time in hopes of finding a leak.

2 weeks later (yesterday) there was little to no refrigerant left. I borrowed an AC sniffer/ UV light from a friend and found that the connections at the condenser were leaking. I replaced the seals last night, pulled a vacuum on the system for about 40 minutes (pulled down to 28inches). I let it sit another 30 minutes with the valves closed and the pump off and saw that the gauge had not moved. I went ahead and charged the system.

Today, my wife gets in the car and the AC won't work. Haven't got to check yet, but I am assuming its low.

What am I missing? With the vacuum test turning out as good as it did I can't understand how it would leak down so quickly.
Click to expand...
 
If it's the system I think it is the expansion valve may be sticking or plugged and causing high pressure and making leaks occur.
 
You can still have a leak even if you hold in a vacuum state for half hour. I suspect you have a leak elsewhere. The dye you used always will show a leak...grab your glasses and a black light. Look at the evap core drain...And everywhere else where refrigerant flows. You will see something I'm sure.
 
High pressure side combined with movement in those modern snap together connections make for leaks that wont show under vacuum.
Your dye may show up at center of compressor clutch/pulley too.
 
I never assume that a "second trip" with a problem means the same problem. You might have something else going on.
 
I second the suggestion about the evaporator core leaking. As suggested check your evaporator drain hose with the UV light (wear those yellow Elton John looking glasses too. They'll help you see it much better). You can also see if there is any UV dye in the water that drips out from it if you can't crawl under the car to get to the drain hose. Also look down in the vents with the light & in the heater duct for any traces of dye.
Also make certain the service valves aren't leaking. If you have a leak there it won't show up with a vacuum stability test because the gauge hoses are still hooked up & sealing the system.
DON'T USE STOP LEAK no matter what! It causes more problems than any good! (cue the guys that will say "I've used it in my car blah blah blah!")
 
Another thought; You didn't mention how many miles are on the car, but if the compressor clutch is worn & the air gap is too wide it may be too much for the magnetic coil to pull the clutch closed. They can be very intermittent when they 1st wear out & work sometimes until it gets hot.
 
I had a similar condition in my 2007 Camry Hybrid. Eventually they put dye in and still had trouble finding it. They finally told me the evaporator coil was leaking. Replacing evaporator coils under the dash of new cars = multi $. About $2K later, I was good to go.
 
If it is the evaporator coil, do some research on this as the jeep ones in 2000 were notorious for being bad and ma mopar put a 10 year 100,000 mi warranty on them.
 
zakimodo said:
Sorry Not an old Mopar.... but a newer one.

This is a 2010 Dodge Avenger (RT 3.5l)

This spring my wife noted that the AC in her car wasn't working. I checked the system and found it was low on charge (just enough to not override the pressure switch). I recharged it and all was well. 3 weeks later it was low again just like before. I decided to recharge with some dye this time in hopes of finding a leak.

2 weeks later (yesterday) there was little to no refrigerant left. I borrowed an AC sniffer/ UV light from a friend and found that the connections at the condenser were leaking. I replaced the seals last night, pulled a vacuum on the system for about 40 minutes (pulled down to 28inches). I let it sit another 30 minutes with the valves closed and the pump off and saw that the gauge had not moved. I went ahead and charged the system.

Today, my wife gets in the car and the AC won't work. Haven't got to check yet, but I am assuming its low.

What am I missing? With the vacuum test turning out as good as it did I can't understand how it would leak down so quickly.
Click to expand...

Leak at the valve/ports you hooked it up to after you disconnect?
Evap leak? Find a way in there to check eg fan resistor.
 
X2 on mopar evaporators. They are a real PITA to get to, so they are hard to check.

I have had two out of 3 durangos go bad on me. Right around 80-100K
 
Lonewolf3165 said:
Another thought; You didn't mention how many miles are on the car, but if the compressor clutch is worn & the air gap is too wide it may be too much for the magnetic coil to pull the clutch closed. They can be very intermittent when they 1st wear out & work sometimes until it gets hot.
Click to expand...
Car has 100K on it. The compressor on this is clean.

When I checked the car last night it has 0 refrigerant left. There was plenty of dye inside the low side service port. I swapped out the Schrader valve re-checked my connections at the condenser. Pulled a vacuum and again it held, I gave it enough charge last night to kick the compressor on. We will see if it help anything tonight.
 
Thanks for the input everyone.

I found the issue.

First, I found that the manifold set I had borrowed from a friend has a serious flaw with the service port connectors. When you pull a vacuum something inside of them is acting like a check valve causing the system to only pull a vacuum on the service hoses/manifold :BangHead:. So every time I thought I pulled a vacuum. Nothing on the car was being evacuated.

After finding this out and using another manifold set I was not able to hold a vacuum. I pressurised the system with air from my compressor and got out the soapy water focusing on where I thought I had a leak at the condenser. Sure enough, the seam between the mounting block for the high-pressure line and the condenser had a crack. Replaced the condenser and away we went.
 
It is a little late, now, but just an FYI. You should never pressurize an A/C system with air from a compressor. There is too much moisture in "shop" air. It can cause future problems. The reason to pull a vacumm on the system, is not to just get the air out, but to remove moisture. The more moisture in the system, the longer you must leave the vacumm pump on.
 
Charrlie_S said:
It is a little late, now, but just an FYI. You should never pressurize an A/C system with air from a compressor. There is too much moisture in "shop" air. It can cause future problems. The reason to pull a vacumm on the system, is not to just get the air out, but to remove moisture. The more moisture in the system, the longer you must leave the vacumm pump on.
Click to expand...

X2. use refrigerant, Nitrogen, or if you have nothing else, CO2.
 
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