Air con re-gas/top up?

[Philip]

Taking my ‘91 model in for the air con to be re gassed or topped up. Anything I should be aware of to avoid perhaps before I take it in?

[goldnsx]

New receiver? Maybe new valve inserts.

[britlude]

He probably won't have R12, unless he has an old secret stash..... So will probably have to fit port adaptors for his R134 machine....

[goldnsx]

Retrofit Kit?

[Kaz-kzukNA1]

Hi, Philip.
I think I know your NSX but not easy for me to link the userID with each owner so I'm going to just reply as a general guidance and not specific to the condition of your HVAC system.

If it's 91 model and since we are in Europe, R12 is prohibited unless it's already in use inside the existing system so can't be topped up or re-gassed.
Probably already converted or using alternative refrigerant.


Not sure how many years it took before you started feeling the needs for the a/c service but to answer your question, it all depends on the health of your system.

If you have slow leakage that takes years before you start feeling the drop in a/c performance, then topping up can be a candidate for a quick temporary fix to keep you moving.

Please remember that the compressor oil travels throughout the system via refrigerant and if you are losing it, you are also leaking the oil outside as well as reducing the amount returning to the compressor chamber.
NSX A/C control doesn't have high rpm protection algorithm so even when you are in VTEC region, it will engage the compressor.
Eventually, it will kill the compressor due to lack of lubrication.


If you are feeling the lack of performance within a few years, take it to the a/c specialist, have it leak tested, fix it and re-fill from scratch.
When evacuating the remaining refrigerant, the HVAC station would tell how much oil was taken out during the process although it doesn't tell how much was lost through the leakage.
A/C specialist should be able to tell you the next step to follow.


If you need to keep doing something every year with your system, it's time to consider major service before it gets to the worst case scenario.
You don't want the compressor getting really noisey and splashing the metal flakes everywhere inside the pipe and the condenser(s).



I'll be doing the major service for another owner in the near future….



Kaz

[Philip]

Hi, Philip.
I think I know your NSX but not easy for me to link the userID with each owner so I'm going to just reply as a general guidance and not specific to the condition of your HVAC system.

If it's 91 model and since we are in Europe, R12 is prohibited unless it's already in use inside the existing system so can't be topped up or re-gassed.
Probably already converted or using alternative refrigerant.


Not sure how many years it took before you started feeling the needs for the a/c service but to answer your question, it all depends on the health of your system.

If you have slow leakage that takes years before you start feeling the drop in a/c performance, then topping up can be a candidate for a quick temporary fix to keep you moving.

Please remember that the compressor oil travels throughout the system via refrigerant and if you are losing it, you are also leaking the oil outside as well as reducing the amount returning to the compressor chamber.
NSX A/C control doesn't have high rpm protection algorithm so even when you are in VTEC region, it will engage the compressor.
Eventually, it will kill the compressor due to lack of lubrication.


If you are feeling the lack of performance within a few years, take it to the a/c specialist, have it leak tested, fix it and re-fill from scratch.
When evacuating the remaining refrigerant, the HVAC station would tell how much oil was taken out during the process although it doesn't tell how much was lost through the leakage.
A/C specialist should be able to tell you the next step to follow.


If you need to keep doing something every year with your system, it's time to consider major service before it gets to the worst case scenario.
You don't want the compressor getting really noisey and splashing the metal flakes everywhere inside the pipe and the condenser(s).



I'll be doing the major service for another owner in the near future….



Kaz
Hi Kaz,
you do indeed know my car. You had it for a couple f months and carried out a lot of work on it which you blogged on this forum.
The reason I want it re gassed is not because of any leaks. It’s purely because it’s not blowing out ice cold air any more.

[Kaz-kzukNA1]

Hi, Phil.

From the photo I took and also as in the Health Check report, your drier/receiver sight glass was already showing/stained in brown debris several years ago.

I couldn't see the refrigerant flow but at that time, I wrote that at least your a/c was still working.

I don't know exactly when you got that brown marking/stain.

There was a sign of leakage at the bulkhead where the evaporator fittings are located near the blower fan motor housing.

If you are saying that your a/c is no longer blowing ice cold in just a few years, then as mentioned above, please take it to the a/c specialist, measure the pressure and inspect for the leakage first.

Also, you can check the 2 x 10A fuse for the R & L Condenser fans inside the pentagonal/octagonal black box under the bonnet.
You can listen for the high speed fan motor sound just in front of each front tyres.
If you can't hear them, the fuse is blown or the motor has seized.
When the car is at speed, there will be enough air flow than the fan speed so your a/c still should work under this condition.
You can spray water at the condenser fins to see any changes in 'condensing' efficiency.

It is there to 'condense' the high pressure/temperature refrigerant gas into liquid state by releasing the energy by cooling it down when passing through the condenser.

Therefore, if the high side pressure is not high enough, condenser fan not operating or condenser fins are all blocked, it can't condense the refrigerant efficiently and thus, allowing gas state of refrigerant into the exp valve resulting in not ice cold air.

Regards,
Kaz

[Philip]

Thanks for the info Kaz, I will pass your comments on to the air con guys and see what transpires.

Many thanks,

Phil

[Philip]

Well this is turning out to be not so straightforward. The garage tell me that I have an outlawed fluid in my system, and to renew with the latest spec fluid, I need a new pump and condensor. They are now trying to track down the parts needed.

[goldnsx]

Alert! Cheat-Alert!

[Philip]

Alert! Cheat-Alert!
Tell me more??

[britlude]

Hmmmmm it's desirable to change these when going from the now illegal R12 to the R134, but not necessary.... As I understand it, the R12 lubricant oil doesn't dissolve in the R134 fluid so the system should be flushed to get most of it out then filled with R134 and the appropriate oil... Mines been ok since this was done in 2014, but I'm changing the pump soon as it's beginning to get noise... Now this may be to do with the AC fluid change, but more likely to do with the 150k miles...

[goldnsx]

There's no reason to change (expensive!) parts while going from R12 to R134a except a new drier.

Or did your compressor blow up?

[Philip]

No, the compressor seems fine. The garage said they cannot re gas with R12 anymore?

[goldnsx]

R12 is forbidden in some small 'environmental-friendly' countries while they juggle with Freon-cans in the backyard of some US households. :) Double moral at its best.

The problem the shop has is to suck the R12 out. Not all are willing to do this as they need a separate station for it as you should not mix R12 with R134a. As R12 is forbidden not they might have disposed the old station. That's why most say they can't do it.

That's why it's a wise thing to use R134a. A retrofit kit and a new trier (R134a version since 1993 in the NSX) is needed only, nothing else (maybe 2 new valve inserts from eB China). If they still want to throw more parts at the car it's better to find a better shop...

[Kaz-kzukNA1]

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Hi, Philip.
Can't remember whether your system was already converted or not.
Could you check the shape of the charge valve?

The easiest one to check is the high side valve located behind the R-side headlight marked in yellow.

For safety reason, if you are not familiar with the HVAC system, best not to remove the cap.
You can tell the shape of the valve without removing the cap.

If removing the cap, please wear protective glove and glass, cover the valve with the shop towel in case of sudden refrigerant leakage.
If you don't have protection glass, at least move your face away from the valve.
You could experience ice burn or even lose eye sight.


Which type (R12 or R134a) of charge valve do you have on your existing system?
If retro-fit kit was used in the past, you will see extra parts (adaptor fitting) on top of the original valve.

Normally, you can find a sticker with big '134a' logo under the bonnet if converted or in use from the factory but it can peel off from time to time.
Depending on your answer, it will change the direction of the further recommendation.


Kaz

[Philip]

Thanks Kaz, here is a pic. The cap is black13545

[Kaz-kzukNA1]

So, unless someone removed the adaptor or created the adaptor joint on the equipment side (seen it done in Japan....), your system is still the original R12 and you have either the R12 or R12 compatible refrigerant in the system.
The brown stain markings at the sight glass is very likely to be the contaminated mineral oil (R12 spec) or something similar.
Basically, not normal.

If this is in Japan, the R12 refrigerant can be purchased legally but no longer allowed to be manufactured or exported.
Still, I was told that during the manufacturing process of certain products, R12 is inevitably produced so it won't disappear....


As goldnsx mentioned, probably the place you visited didn't like the idea of recovering the R12 refrigerant from your system.


Anyway, in UK, there are several options for you.

1. Alternative refrigerant
I'm not fan of this but I think several owners are using it.
Not sure where you are based but there is a company called [Bee Cool Air Conditioning Services (ACS)] in Northampton, NN16 8LD where several NSX owners have already visited.
http://www.bee-cool-aircon.co.uk/

I think Mike - @sorepaws is one of them who had the alternative refrigerant charged into his original R12 system.
May be PM him or just contact Bee Cool if you live nearby???


As long as your compressor, exp. valve, etc are tired but operating fine, you can re-use them.
You are very likely to be asked to replace the drier/receiver.

Although you have fair amount of leakage and thus, worth considering the Retro fit as per next section, this will be the cheapest and quickest option for you to keep moving before moving to the next stage.


2. Retro fit - basic
If your compressor is still operating fine (for now) and can be re-used, considering the contamination, I don't think it's worth the next step 3 (Retro fit - advanced) unless you are ready to flush the entire system and replace the compressor, etc.

Strictly speaking, due to the boiling point difference between R12 and R134a, you need higher energy exchange capacity at the condenser for R134a.
Therefore, the advice from your a/c specialist is somewhat correct but unless the fins are smashed or the fitting thread is stripped, you can keep using your existing R12 spec condenser.
It's the matter of efficiency and how far you want to go but for this basic retro fit purpose, I won't replace it.

During the Honda Refresh program at the factory, if the existing R12 system was blowing cold air with the compressor making no abnormal noise or no major leakage, all they do is to install the adaptor charge valve, replace drier/receiver and put PAG oil designed for the retro fit purpose.

They won't flush the system.
They will re-use rest of the original R12 components such as the compressor, condenser, exp. valve, o-ring, flex hoses, etc.
For your reference, I don't like the OEM adaptor charge valve included in the retro fit kit.
Honda may have already changed it but I always recommend the one from Denso Japan.


When retro fit was first introduced in the early 90s', there were lots of scary negative stories.
However, as the history proved, while it's ideal to have clean system and replace the parts to R134a spec, for mainly cost and time saving purpose, you can keep using majority of the R12 parts even at the time of converting to the R134a refrigerant.

The old R12 spec mineral oil will stay inside the lower part of the system as it can't travel via R134a refrigerant or it will be neutralised and remain as a certain 'debris' if specific PAG oil used at the time of conversion.
It will reduce the efficiency slightly but most likely, you won't notice it.


If your existing system is healthy with no major leak, this option would last for many years.
However, if your compressor was already making noise or the system have major leakage (resulting in reduced compressor oil amount), there were lots and lots of premature failure reported within a few years after the conversion.


3. Retro fit - advanced
You are going to replace at least the compressor, exp. valve, drier/receiver, o-ring, shrader valve, etc and must flush the entire system, ideally by disabling the exp. valve needle.
I'll be doing this for another owner soon as the owner was forced to replace the evaporator any way.

Time consuming, expensive and require some NSX experience so not everyone's cup of tea.



Hope you can find the suitable option for your target.


Kaz

[britlude]

can you not seek a second opinion from another air-con service place that is less intent on ripping off its customers? the mobile ac guy that did mine knew the score, had the conversion kit (it's only screw on adaptors) and away he went!!!

the AC techs have to deal with removing R12 on a regular basis i'm sure

[Philip]

Thanks for all the advice guys, especially Kaz �� looks like I will be off to Bee-cool soon.

[Philip]

Car is booked in at BeeCool this afternoon. Will report back if the visit is successful.

[Philip]

Hooray. Just got back from Bee Cool who have drained my old air con refrigerant out and replenished with R27 I think they said it was. No need to change any components and I now have lovely ice cold air con again.
I can thoroughly recommend them. Apparently, they look after Ross Brawn’s NSX too.

[sorepaws]

Glad they did a good job for you, I have had my car done by them twice over the past 6 years. To my knowledge they have been involved in the aircon of over 7 NSX - the gas is RS24 typically used in older cars like Rolls Royce when R12 was being phased out.

[Jezzerr]

Yep, here's another thumbs up for Bee Cool who did mine last year!