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Welcome to the Forum, from Cave Creek AZ.
 

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Spotting leaks in the evaporator is particularly difficult, espcially since the condensation drain for the WK/XK/WK2 is above the transmission and just drips over the transmission.
You have difficulty spotting the UV dye from the drain.

You have to diagnose it from the hi/lo pressures and temperatures from different vents, etc.... ....I had a leaky evaporator and couldn't conclude it for myself trying to diagnose it, I've had pro's describe what you should see for a leaky evaporator and its clear it takes a pro that has done this everyday for years to be able to notice the subtle differences and reactions. Not you or me with a set of hi/low pressure gauges.
My research points to this Amazon.com: InterDynamics Certified AC Pro Car Air Conditioner Hose and Gauges for R1234YF Refrigerant, Recharge Kit for Cars & Trucks & More, Reusable, 24 in, CERTYF102-4: Automotive
And you will also need refrigerant. See this first
It may not be a good idea to do it yourself. You can introduce moisture in the system, and low side pressure is not exactly a good indicator of how much to add.
The guy in the video is wrong, the AC system is a closed system, ambient pressure (air pressure or altitude) has no affect on the pressures in the system.
Does it affect the measurement from the gauges? Maybe, I'm not sure. I think the gauges are for absolute pressures and not gauge pressure.

Yes, you really should have a high side pressure to compare with the low side and against a table in the FSM. If you have DiagFCA or AlfaOBD, or a similar tool, you could read the AC pressure transducer pressure, which is the high side pressure.

And no you likely won't get any air or moisture in the system using that device or gauges, usually you loose a little refrigerant connecting to the system, which purges the tiny bit of air/moisture that could be in the connector. There is a desicant bag in the system that is suppose to absorb the moisture, maybe even the oxygen, it likely will handle the tiny bit that might come from connecting the hoses.
I wonder if one of those recharge/sealant type diy would have selaed that? Unless those things only work in small stuff like leaking o-rings.
Most pro's recommend against sealants in the AC system, it can clog up and make a mess of the system. Most sealants are for O-rings and seals, not cracks or pin holes. There are some scabbing sealants that coagulate when they are exposed to air to form a scab over the leak, but even the lowest pressure at the evaporator is still over pressure of normal atmosphere, I doubt a scab would hold over a hole or crack in the system. Its more for forming a scab outside the barely leaking O-ring. I suppose it might be possible, but not likely.

The evaporator is all metal, they usually develop a crack or pin hole. Its possible they may leak from the seals where their lines connect, at the Thermal Expansion Valve, but likely your mechanic would say its leaking at the expansion valve if that was true.
I am under impression that the refrigerant contains some UV fluorescent dye? So get a blacklight and look around engine bay and under the dash. If there is something leaking maybe it will show up?
Or does one need to add dye by themselves?
A lot of OEM and Aftermarket include UV Dye in their refrigerant, but its not guaranteed. Perhaps the spec for R-1234yf requires uv dye in all products, I've seen things implying that.

If you want to add dye or sealant, you purchase a recharge can that includes that already mixed with the refrigerant in the can and service the system with it. The same for oil, but the refrigerant in the can forces the oil out of the can and into the system, make sure you read the instructions, some cans must be held upside down and others right side up.
 

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So mine just started doing the hissing behind the dash, then I see this thread....smh.

I have MaxCare warranty, so I guess I need to make an appointment to have it looked at.
 

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Discussion Starter #64
So mine just started doing the hissing behind the dash, then I see this thread....smh.

I have MaxCare warranty, so I guess I need to make an appointment to have it looked at.
Sorry it’s happening to you. Will you check back after you know what is wrong? Thanks
 

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Just got diagnosed with same problem. Had the hissing noise. Mechanic says it's the evaporator. Can anyone who had it done out of warranty advise how much it cost?
 

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Just got diagnosed with same problem. Had the hissing noise. Mechanic says it's the evaporator. Can anyone who had it done out of warranty advise how much it cost?
Like people have said on this thread, a hissing noise from the evaporator does not necessarily mean the evaporator is leaking. You could simply be low on refrigerant and its causing the hissing noise from the expansion valve. Topping off the refrigerant is many times less expensive than replacing the evaporator.

It might be best to take your vehicle to an AC Speciality shop, they likely would be far better at diagnosing the problem than a Dealership.

If you do have a leak in the evaporator, replacing it will require removing the entire Dash. This will easily cost $1000-$1200 in labor with the cost of evaporator and reservicing the system.
 

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So is topping of the refrigerant a fix or a temporary fix?
 

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So is topping of the refrigerant a fix or a temporary fix?
It depends on how big the leak is and whether you find and fix it first. In the case at hand the fix could range anywhere from

replace evap - at least $1000, probably closer to 2k
find and fix a routine leak - 2 to 5 hundred
top up the system, no significant leaks found - 1 to 3 hundred
 

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It depends on how big the leak is and whether you find and fix it first. In the case at hand the fix could range anywhere from

replace evap - at least $1000, probably closer to 2k
find and fix a routine leak - 2 to 5 hundred
top up the system, no significant leaks found - 1 to 3 hundred
Yep all about Quality of life. Could be simple valve core $15 part to change etc
 

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So is topping of the refrigerant a fix or a temporary fix?
We don't know what is wrong, so how would we know what the fix is?
Remember, I said it could be several other things than the evaporator, not that it is definitely one thing. No one can diagnose an AC system just off a sound.
I'm betting your mechanic said, "might be", "could be" or "probably" the evaporator, not just "its the evaporator". He's not a very good mechanic if he is decides its a bad evaporator on just a hiss sound.
You need to have this diagnosed and it will require Hi/Low side pressures and temperatures and go through troubleshooting procedures. And an experience AC tech can analyze the pressures much better than a mechanic or dealership. That is why I said you should take it to an AC Shop.

The AC system is hermetically sealed, unless it leaks, it should never need topping off. So yes, if all you do is top it off, its a temporary fix. It depends on how bad the leak is, in how temporary the fix is. It might go another 6 years before needing servicing again. By Law the shop should do some sort leak check and attempt to fix it, before servicing it again, but AC leaks can be hard to track down. They will also troubleshoot the system and maybe able to tell if you have an evaporator leak causing the hissing or a bad expansion valve, or a slow leak that system is being low on refrigerant is causing the hiss noise.
 

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We don't know what is wrong, so how would we know what the fix is?
Remember, I said it could be several other things than the evaporator, not that it is definitely one thing. No one can diagnose an AC system just off a sound.
I'm betting your mechanic said, "might be", "could be" or "probably" the evaporator, not just "its the evaporator". He's not a very good mechanic if he is decides its a bad evaporator on just a hiss sound.
You need to have this diagnosed and it will require Hi/Low side pressures and temperatures and go through troubleshooting procedures. And an experience AC tech can analyze the pressures much better than a mechanic or dealership. That is why I said you should take it to an AC Shop.

The AC system is hermetically sealed, unless it leaks, it should never need topping off. So yes, if all you do is top it off, its a temporary fix. It depends on how bad the leak is, in how temporary the fix is. It might go another 6 years before needing servicing again. By Law the shop should do some sort leak check and attempt to fix it, before servicing it again, but AC leaks can be hard to track down. They will also troubleshoot the system and maybe able to tell if you have an evaporator leak causing the hissing or a bad expansion valve, or a slow leak that system is being low on refrigerant is causing the hiss noise.
All AC systems leak, it's just a question of how much. The A/C fittings have a SAE acceptable leakage rate of 1/4 ounce of refrigerant per year per fitting. That does not sound like a lot, but the average vehicle has 8 fittings. This means that a system operating within specs can still lose as much as 2 ounces of refrigerant per year. The total charge is 22 oz. At max spec leak rate at 4 years it could be about 40% low. 40% low is when you will notice significantly reduced cooling. Most systems will need/benefit from some make up refrigerant by 10 years even if they are not "leaking". Some will need it by 5 years.
 

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All AC systems leak, it's just a question of how much. The A/C fittings have a SAE acceptable leakage rate of 1/4 ounce of refrigerant per year per fitting. That does not sound like a lot, but the average vehicle has 8 fittings. This means that a system operating within specs can still lose as much as 2 ounces of refrigerant per year. The total charge is 22 oz. At max spec leak rate at 4 years it could be about 40% low. 40% low is when you will notice significantly reduced cooling. Most systems will need/benefit from some make up refrigerant by 10 years even if they are not "leaking". Some will need it by 5 years.
The Jeep moto if it anit leaking there anit nothing in it.
 

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All AC systems leak, it's just a question of how much. The A/C fittings have a SAE acceptable leakage rate of 1/4 ounce of refrigerant per year per fitting. That does not sound like a lot, but the average vehicle has 8 fittings. This means that a system operating within specs can still lose as much as 2 ounces of refrigerant per year. The total charge is 22 oz. At max spec leak rate at 4 years it could be about 40% low. 40% low is when you will notice significantly reduced cooling. Most systems will need/benefit from some make up refrigerant by 10 years even if they are not "leaking". Some will need it by 5 years.
I understand what you are saying, but I have to disagree. I'd prefer to put it as "No AC system will remain leak free forever". Yes there may be engineering tolerances that allow a certain level of leaking, that does not mean they will leak.

Remember the argument we have about oil consumption, with FCA falling back on the old standard (it might be an SAE standard?) Up to a quart per 1000 miles is acceptable. While most modern engine don't consume more than a few ounces per 7500 miles.

Yes, its very difficult to keep an AC system sealed in a automobile, its a system that requires many joints that are bolted together and sealed with composite materials, that suffers shock and vibration, with a small molecule under high pressures, 100's of PSI while operating and 90 PSI even while static. The turning shaft of the Compressor has the seal under friction and will wear.

I have measured the refrigerant charge in a 6 y.o. vehicle I owned with an full service AC machine, long story, we were testing out the machine the hobby shop just got, and it measured the exact same weight of charge as the sticker says its suppose to be. I agree, eventually all AC system will leak, I disagree that all AC systems are leaking from the beginning, in any measurable amount.

I totally agree also, AC leaks can be very difficult to find. The EPA requires you have to attempt to fix any leak before topping off any AC system. "Attempt" is left open to interpretation, simply adding dye or tighten all the fittings accessible will meet the requirement of "Attempt". So, many times the most practical thing to do is, is to top off the system every couple of years, or even once a year, if you're down to needing to top off within a couple of months, you need to make a bigger effort at fixing the leak.
 

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I understand what you are saying, but I have to disagree. I'd prefer to put it as "No AC system will remain leak free forever". Yes there may be engineering tolerances that allow a certain level of leaking, that does not mean they will leak.

Remember the argument we have about oil consumption, with FCA falling back on the old standard (it might be an SAE standard?) Up to a quart per 1000 miles is acceptable. While most modern engine don't consume more than a few ounces per 7500 miles.

Yes, its very difficult to keep an AC system sealed in a automobile, its a system that requires many joints that are bolted together and sealed with composite materials, that suffers shock and vibration, with a small molecule under high pressures, 100's of PSI while operating and 90 PSI even while static. The turning shaft of the Compressor has the seal under friction and will wear.

I have measured the refrigerant charge in a 6 y.o. vehicle I owned with an full service AC machine, long story, we were testing out the machine the hobby shop just got, and it measured the exact same weight of charge as the sticker says its suppose to be. I agree, eventually all AC system will leak, I disagree that all AC systems are leaking from the beginning, in any measurable amount.

I totally agree also, AC leaks can be very difficult to find. The EPA requires you have to attempt to fix any leak before topping off any AC system. "Attempt" is left open to interpretation, simply adding dye or tighten all the fittings accessible will meet the requirement of "Attempt". So, many times the most practical thing to do is, is to top off the system every couple of years, or even once a year, if you're down to needing to top off within a couple of months, you need to make a bigger effort at fixing the leak.
Aside from the fittings, 30" of barrier hose can leak 3 oz per year. Exact amount will depend on how much you use the AC, temperatures, etc. Barrier Hose Upgrade – Griffiths Not sure how long the hose sections are in the JGC but if it was only 10" that's potentially 1 oz per year of heavy use just thru the hose. 5 years would be 5 oz just from the hose. 5/22 = 20% loss of charge. Lots of variables but IMHO one thing is certain, they all leak, it's just a question of how much.
 

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Aside from the fittings, 30" of barrier hose can leak 3 oz per year. Exact amount will depend on how much you use the AC, temperatures, etc. Barrier Hose Upgrade – Griffiths Not sure how long the hose sections are in the JGC but if it was only 10" that's potentially 1 oz per year of heavy use just thru the hose. 5 years would be 5 oz just from the hose. 5/22 = 20% loss of charge. Lots of variables but IMHO one thing is certain, they all leak, it's just a question of how much.
Again, I think you're looking at tolerances allowed before rejection. With R-134a they switched to PCV (I forget the actual material, but a flexible and less permeable material) lined hoses to prevent the refrigerant molecules from diffusing through the rubber hose. I have seen AC systems not loose any measurable amount of refrigerant for years. Yes, in the automotive application the challenge to keep it sealed is very difficult, some are leaking as soon as first assembly. Eventually jolting and vibration is going to cause leaks, as well as just degradation of the composite seals. And usually the biggest source of leaks is the seal to the compressor shaft.... ....you've got a tight seal around a high speed turning shaft, its going to wear.
 

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I’ve decided I’m just gonna top Off the system with the r1234yf for around 75 bucks. No way am I gonna go through the headaches as to why it’s leaking or spend $2000-$2500 on servicing or replacing parts on a vehicle that I plan on getting rid of in another year or two.
 

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I’ve decided I’m just gonna top Off the system with the r1234yf for around 75 bucks. No way am I gonna go through the headaches as to why it’s leaking or spend $2000-$2500 on servicing or replacing parts on a vehicle that I plan on getting rid of in another year or two.
Are you going to DIY? Or take it to an AC Shop?

There are all sorts of pitfalls to servicing the AC system yourself using the cheap cans with a gauge on it. One nice thing about the WK2 AC system, it set a codes and light the Cell if it detects hi-side pressures being too high while your driving with the AC on, meaning it warns you if you over serviced the system.

A shop services it for you, if they know what they are doing will be able to tell if you have problem other than a slow leak. Expect a dealership not to have that experience.

How soon you will have to top off the system, will tell you how bad the leak is.
 

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Are you going to DIY? Or take it to an AC Shop?

There are all sorts of pitfalls to servicing the AC system yourself using the cheap cans with a gauge on it. One nice thing about the WK2 AC system, it set a codes and light the Cell if it detects hi-side pressures being too high while your driving with the AC on, meaning it warns you if you over serviced the system.

A shop services it for you, if they know what they are doing will be able to tell if you have problem other than a slow leak. Expect a dealership not to have that experience.

How soon you will have to top off the system, will tell you how bad the leak is.
I plan on doing it myself. I’ll buy the $30 hose and gauge to verify it’s low. If is then I’ll get the small can of Honeywell R1234yf for $35-$40 to add as needed.
Right now it blows cold air. Not super cold, but cold enough. When I bought the vehicle in November 2019, I really didn’t get to test it out to see how cold it got. It’s not bad but could be colder I think. I don’t remember it making that noise when I bought it or I would’ve had the dealer service while the warranty still had a few months to go. It’s a 2017 model and it like to possible keep it until 2022. It’s out of warranty so I’d like to not dump a lot of money into it.
 
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