AC service caps for Honda, do they provide seal the AC system?

[GJHANS]

The CR-V is 20 years old and I'm considering replacing the service caps. Do the cap seals fail with age? I can't find High and Low pressure caps online that fit the Honda. The Honda dealer only carries the High pressure cap as the Low pressure cap has been discontinued. The caps look similar to those in the photo below.

I've read contradictory information regarding the function of these caps. Some folks online state that the cap is the primary seal and help keep refrigerant from leaking from the AC system, with the Shrader valve being the secondary seal. Others say the caps function to prevent dirt, etc from contaminating the Schrader valve and that it's the valve that seals the system. I hope one of you can answer this.

1. If the caps are critical, does anyone know a source where I can purchase the caps for a 2005 Honday CR-V?
2. If new replacement caps are not available, could I place a new AC o-ring seal (green as shown in photo below) in each cap? If so, do I need to remove the old seals first?
3. If these caps rarely fail, maybe I should leave well enough alone and continue to use the original caps as is?

Thank you

The refrigerant was recovered/recharged today and the AC technician said the system only contained 8 oz and required 18 oz. With a calibrated thermometer and with the AC set on "Max", the temperature from the central vent fluctuated between 36-40 degrees while driving. Ambient temp was 78 degrees.

[JohnHere]

If the caps aren't cracked or broken and the inner seals are intact, chances are you can continue to use them. I had a 1994 Toyota Camry Wagon, bought new, that up until a year ago had the original caps that never leaked.

Take a look at the inner seals using a magnifying glass and a strong light. If you don't see any cracking or worn areas, I'd say that they are still good. While you have the caps off, put a small dab of Nylog Blue (available from ACKits.com, this Forum's sponsor) on each internal seal and the sealing edge and threads of each service port before screwing the caps back on.

And yes, each cap is the primary seal, and each Schrader valve is the secondary seal, just the opposite of what most people think. The original internal cap seals usually have a square configuration while an o-ring is round, so I wouldn't replace the seals with o-rings over concern that the o-rings might leak.

Seasonal refrigerant losses occur from the compressor shaft seal, so after a number of years, you'll need to recover, evacuate, and recharge the system, just as you did, to restore cooling efficiency. The slight leakage from the compressor shaft seal is normal and expected.

The refrigerant was recovered/recharged today and the AC technician said the system only contained 8 oz and required 18 oz. With a calibrated thermometer and with the AC set on "Max", the temperature from the central vent fluctuated between 36-40 degrees while driving. Ambient temp was 78 degrees.

The specs that I have for your car are as follows: 18 ounces net weight of R-134a, and 4.5 fluid ounces of PAG-46 oil. The shop was indeed correct about the refrigerant amount.

[Cusser]

I've encountered just a few service valve caps that leaked. One was on a R-12 refrigerator from the late 1960s that lost its charge due to a crack in the seal of the service valve cap (like with vehicles, never expect a service valve schraeder to seal 100%). And a couple of years ago one of the valve caps on my R-12 1988 Mazda truck leaked, but since it still contained about 1/2 charge of R-12, I didn't change that service valve, just the cap (I don't have the tool to change the valves without losing charge).

When I visited the local parts yard a decade ago, I grabbed quite a few R-12 and R134a service valve caps, some like in your photo.

[Tim]

Primary seal? I find the comment laughable but understand the point people are trying to make. Think about it, a service port w/o a Schrader and just a cap. LOL You need both for the best chance for no leaks.

[GJHANS]

While you have the caps off, put a small dab of Nylog Blue (available from ACKits.com, this Forum's sponsor) on each internal seal and the sealing edge and threads of each service port before screwing the caps back on.

The specs that I have for your car are as follows: 18 ounces net weight of R-134a, and 4.5 fluid ounces of PAG-46 oil. The shop was indeed correct about the refrigerant amount.

Thanks everyone, for the comments.

At ACKits.com, the only Nylog Blue I found is sold by the case.

1. Regarding the Nylog Blue, I'm assuming the old Nylog Blue should be removed and reapplied each time the AC is serviced. If so, is there product to remove the old Nylog Blue?

I did ask the tech about the PAG oil. He said he didn't add any since the system was still under pressure before he recovered the refrigerant and mentioned that there should still be sufficient PAG oil in the system.
2. Any thoughts on this?
3. Or is it a good idea to add one or two ounces of oil each time the AC is serviced?

I assume his RRR machine did not have the feature which measures the amount of PAG oil recovered, but don't know.

[Tim]

Yeah, once AMA stopped carrying in locally. The supplier requires it sold by the case.

I suggest this for individual sales.

https://www.ackits.com/product-categori ... lube-24139

[JohnHere]

1. Regarding the Nylog Blue, I'm assuming the old Nylog Blue should be removed and reapplied each time the AC is serviced. If so, is there product to remove the old Nylog Blue?

You could just wipe it off each time a connection is opened (hopefully, you won't be doing that very often ) and re-apply it. There is no Nylog Blue remover that I'm aware of. It's essentially very thick PAG oil, so you won't have any problems mixing the old with the new unless the old is contaminated somehow.

I did ask the tech about the PAG oil. He said he didn't add any since the system was still under pressure before he recovered the refrigerant and mentioned that there should still be sufficient PAG oil in the system.
2. Any thoughts on this?
3. Or is it a good idea to add one or two ounces of oil each time the AC is serviced?
I'm assuming his RRR machine did not have the feature which measures any recovered PAC oil.

I think the tech's statement has faulty logic: "I did ask the tech about the PAG oil. He said he didn't add any since the system was still under pressure before he recovered the refrigerant and mentioned that there should still be sufficient PAG oil in the system." Indeed, many systems still can be under pressure before recovery, and after recovery might not contain sufficient oil if some came out that wasn't measured.

RRR machines that I've seen have a container that collects and measures the oil that typically comes out after refrigerant recovery so that the same amount of oil can be put back in. Yes, oil will still remain in the system. Whether it's sufficient for the "health" of the compressor is the big question. If, say, 2 ounces out of 4.5 ounces of oil (more than 44 percent) come out with the refrigerant, I'd definitely want to replace that.

[GJHANS]

I purchased a couple of new caps at NAPA today. I'm guessing they should be installed until they are snug, and then tighten just a bit more. But maybe someone can let me know how much force is needed when installing the caps in order to avoid refrigerant escaping.

Thank you

[JohnHere]

I purchased a couple of new caps at NAPA today. I'm guessing they should be installed until they are snug, and then tighten just a bit more. But maybe someone can let me know how much force is needed when installing the caps in order to avoid refrigerant escaping.

The caps are usually plastic, so don't over-tighten them. No wrench or pliers needed. Finger-tight is sufficient after lubing the inside of the caps and the exterior of the service ports with a light coat of Nylog Blue or PAG oil.