First off, thanks to Moparman and IBMobile's A/C troubleshooting tips. I'm not mechanically inclined, and A/C is a mystery to me,  but after spending a good portion of the day reading, and watching videos I'm starting to understand. 

 

Some background - took to the shop, mechanic recharged and put dye in, A/C was good for ~1 month then started blowing warm. Took back, he couldnt find the leak, recharged with dye and kept it for a week, blowed for ~1 month, now it's warm again. I believe he used a Freon with leak patch.

 

Since it's a time and money commitment to get it to him, I got a loaner Manifold gauge and Vacuum pump and set it up tonight.

With the truck off, not warmed up:

LOW side = ~82

HIGH side = ~80

 

Should I have started the truck up and measured like that? "Dodge along with other manufactures suggest to do it with: the engine at full operating temperature, the engine rpms at 1000 (others say up to 1500rpm),  A/C control set to A/C-Max, temperature control to cold,  fan speed at max (others recommend a medium fan speed), doors and windows closed with thermometer in the center vent. "

 

It's ~85 degrees here, so per IBMobile's guide, my High side should be 190+ so that means my problem is:

 

{

Refrigerant is low or restriction in accumulator or evaporator.

High Side:  Low      

Low Side:   Normal

}

 

Am I on the right track?

 

When truck is warmed up, the Compressor/Clutch kick on and off multiple times a minute making me think the refrigerant is low...but it's weird cause the mechanic recharges, it blows cold for a month, then blows warm even with a decent Low number...

 

I've seen two guys on Youtube reporting that they replaced their A/C Orifice Tube line and Accumulator/Receiver/Drier to fix it. Should I just do that? Or are there some more steps I should take?

To pull those two units, do I need to evacuate the entire A/C system?

 

The Evaporator is near the heater core, which basically requires a dash pullin, right?  Any simple way to dye test, or sniffer test this? 

 

_______________________________________________

tl;dr AC blows warm. Took to mechanic twice, he couldnt find leak. He recharged and used a leak patch with dye. Measured with A/C Manifold tool and LOW=82 and HIGH=82. Should I just replace the Orifice tube line and Accumulator? Or is my Evaporator shot?

  On 9/8/2022 at 2:31 AM, jaredwins said:

LOW side = ~82

HIGH side = ~80

That shows that the static high and low sides pressures have equalized and there is enough pressure to close the low-pressure switch and energize the clutch coil.

 

I check temperature output with the engine speed at 1500 rpm, temp to max setting, fan speed at medium, doors and windows closed with thermometer in the center vent.

 

  On 9/8/2022 at 2:31 AM, jaredwins said:

I've seen two guys on Youtube reporting that they replaced their A/C Orifice Tube line and Accumulator/Receiver/Drier to fix it.

That will not fix your problem.  You have a good size leak, and your system is low that's why the clutch keep coming on and off.  Since dye has been added to the system with the special glasses and UV light look at all the fittings, front compressor seal (between the compressor body and pully), and condenser for leaks.  If no leaks found at these areas, then the evaporator becomes suspect.  Check the water drain for the evaporator for any telltale sighs; you may need an electronic leak detector placed at the end of the drain for this. 

 

Below is one of the pressure charts I use.

  On 9/8/2022 at 2:31 AM, jaredwins said:

 

 

You're a mechanical wizard my guy! 

 

I'll get to work trying to find the leak. Again, forgive my ignorance, but how long does that UV Dye last? The mechanic added it about a month ago, so does it disappear after that amount of time? Should I get a bottle of dye and some refrigerant and circulate it through the pickup for an hour to charge the system and give me a better chance of seeing the leak/dye? 

 

I've seen some guys use soap and water instead of dye... would that be an option here? Or is the dye and sniffer my best bet?

 

"Check the water drain for the evaporator"

Is that the small black drain nipple that is located on the passenger side firewall  (engine compartment side) just under the PCM? Should I look for dye coming outta there, indicating a leak from the evaporator? Should I get a sniffer and shove it up inside that water drain? 

 

 

The leak detector dye should still remain in the system, and is probably the easiest way to locate a leak vs using soap and water.

 

Yes, the water drain is located on the passenger side firewall below the PCM. Make sure that it's not plugged up and can evacuate any condensation in the evaporator core.

  On 9/8/2022 at 2:25 PM, jaredwins said:

how long does that UV Dye last?

The dye mixes with the PAG refrigerant oil and lasts forever.  At the point there is a leak there will be fluorescent staining from the dye.

 

  On 9/8/2022 at 2:25 PM, jaredwins said:

I've seen some guys use soap and water instead of dye... would that be an option here? Or is the dye and sniffer my best bet?

Glasses with UV light or sniffer are best.  Soap and water is hit or miss method.

 

  On 9/8/2022 at 2:25 PM, jaredwins said:

Is that the small black drain nipple that is located on the passenger side firewall

what @01_Cummins_4x4 said.

 

  On 9/8/2022 at 2:25 PM, jaredwins said:

Should I get a sniffer and shove it up inside that water drain? 

This method would work the best.

The AC compressor shaft seal is a likely cause of the leak, especially if the compressor has lots of miles on it.  Just inspect the shaft seal area.  If there is an oily mess around it, you have found your leak.  If it is dry, it is not leaking.  The condenser, evaporator, and accumulator are non-moving parts and will only leak if damaged.  Most connections are double-oring sealed and rarely leak, and if they did, the leak would have to present for a long time to affect AC performance.

 

Also, check the high pressure connection for the high pressure gauge.  They are notorious for leaking after removing a high pressure gauge.  Even a new connector leaked on my truck. The leak is masked by the plastic protector cap.  Remove the plastic cap and use a soapy water solution for the test.  

 

I am the original owner of my truck.  The only leak I have ever had is the compressor shaft seal and it was obvious.  I replaced the compressor (about 100,000 miles ago).  All of the other AC components are original.

 

- John

  On 9/8/2022 at 2:54 PM, 01_Cummins_4x4 said:

The leak detector dye should still remain in the system, and is probably the easiest way to locate a leak vs using soap and water.

 

Yes, the water drain is located on the passenger side firewall below the PCM. Make sure that it's not plugged up and can evacuate any condensation in the evaporator core.

 

  On 9/8/2022 at 2:59 PM, IBMobile said:

The dye mixes with the PAG refrigerant oil and lasts forever.  At the point there is a leak there will be fluorescent staining from the dye.

 

Glasses with UV light or sniffer are best.  Soap and water is hit or miss method.

 

what @01_Cummins_4x4 said.

 

This method would work the best.

 

  On 9/8/2022 at 4:09 PM, Tractorman said:

The AC compressor shaft seal is a likely cause of the leak, especially if the compressor has lots of miles on it.  Just inspect the shaft seal area.  If there is an oily mess around it, you have found your leak.  If it is dry, it is not leaking.  The condenser, evaporator, and accumulator are non-moving parts and will only leak if damaged.  Most connections are double-oring sealed and rarely leak, and if they did, the leak would have to present for a long time to affect AC performance.

 

Also, check the high pressure connection for the high pressure gauge.  They are notorious for leaking after removing a high pressure gauge.  Even a new connector leaked on my truck. The leak is masked by the plastic protector cap.  Remove the plastic cap and use a soapy water solution for the test.  

 

I am the original owner of my truck.  The only leak I have ever had is the compressor shaft seal and it was obvious.  I replaced the compressor (about 100,000 miles ago).  All of the other AC components are original.

 

- John

 

Thanks for the info everyone! This has given me some good next steps and I'll get after it 

 

 

Alright guys, I filled up the AC system from the fill valve with about 1/3oz of dye with a can of r134, jumped the compressor wire (on top the accumulator) and let the truck run ~30 minutes with ac on max and vent high. Air started blowing a little cold. About 2 hours later i crawled all over with a UV light tracing tubes and didnt see any leaked dye. Paid special attention to the high and low valves, compressor, condenser, accumulator.... Should I wait a few days and check again? I'm thinking the leak is so small maybe i didnt give it enough time? 

 

I'm a little confused on the drain port... Is there something I should do to test that it's draining? It's definitely draining water to the ground and when i touched it, got few drops water on my finger. So it seems to drain fine? I didnt see UV dye in this water.

 

Below are some pics if it means anything to you. The compressor didnt look like an oily mess to me (no more than the rest of the truck). 

 

compressor:

 

low pressure/fill valve

 

High pressure valve

 

 

drain port near ECM, not clogged. Some condensation drops came out when i touched it. 

 

compressor w/ uv light

 

accumulator w/ uv light

There was dye in the system already from previous repair attempts and the dye lasts forever in the system.  The dye will circulate through the system, when first introduced, with in 10-40 minutes of run time.  Do not add any more dye.  There has been plenty of elapse time for a leak to show.

 

If there is a leak at a connection it would have shown.  The evaporator cannot be seen without taking it out of the HVAC case; An electronic leak detector works best for this area checking at the end of the drain tube ao the dash vents with the fan on low speed.  Another place to check is the front of the condenser in front of the radiator.  It could get a pin hole leak from road debris striking it.

The front compressor seal is hidden behind the pully/clutch; look for dye staining at the front bottom of the compressor where the pully is mounted to it. 

    

  On 9/11/2022 at 6:30 PM, IBMobile said:

There was dye in the system already from previous repair attempts and the dye lasts forever in the system.  The dye will circulate through the system, when first introduced, with in 10-40 minutes of run time.  Do not add any more dye.  There has been plenty of elapse time for a leak to show.

 

If there is a leak at a connection it would have shown.  The evaporator cannot be seen without taking it out of the HVAC case; An electronic leak detector works best for this area checking at the end of the drain tube ao the dash vents with the fan on low speed.  Another place to check is the front of the condenser in front of the radiator.  It could get a pin hole leak from road debris striking it.

The front compressor seal is hidden behind the pully/clutch; look for dye staining at the front bottom of the compressor where the pully is mounted to it. 

    

 

I crawled around another 30 minutes cleaning grease from fittings and shining the UV all over the front Condensor looking for leaks from road debris. Also checked the front of the compressor where you marked, and still not seeing any dye. So the evidence for a leak in Evaporator is growing.... I think I'll take it to another shop who has a sniffer and see if they can find it.

 

Thanks for all the help though. Wish I could have found the problem myself  :/ 

 

Compressor front seal behind the clutch might be leaking which will not always have green dye.