Older A/C pre 93

[PeterS]

In the US cars some folks are replacing the R12 in their older cars with a compatible replacement call "Autofrost". http://www.autofrost.com/..and others have replaced the R12 with R134...

The jury is still out as to how much of the R12 system has to be modified to adequately run with the R134...It is a given that the R12 Ester or lubricating oil for the compressor has to be replaced with one compatible with R134, and that the fill port needs an adaptor to work with the R134 equipement.

If the system has been open then it is a good idea to replace the reciever dryer ( the silver colored can). Some folks advise replacement of all the seals with R134 compatible ones, while others including some of the AC techs have stated that the R12 seals are so saturated with oil that this does NOT have to be done.

I think that the bottom line is how well you need the system to work and how much you want to spend. You may infact receive sufficient performance from a straight conversion (vacuum the remaining R12 and ester from the system, and insert the new ester and R134...)

Thats the extent of the conversion done on my CQ...

HTH

[shadquattro]

Air Con. Gas issues

I,m suprised a 92 car has R12,this was around the time it was replaced with R134a, but most manufacturers were well in advance of the changeover.
All modern cars use R134a which is an HFC gas and so far safe to the ozone. R12 is a CFC and depletes the ozone and now obsolete (and illegal) as it has been for around 3 years.

An interim gas FX56 (R409a) is a drop-in replacement for R12 and is widely available and likely to be so for longer than many S2's.
The pressures are similar to R12 and so is the quantity required to recharge a system (less than 1kg).

R134a can be used in an older system but the oil will need to be flushed out with refrigeration flushing agent and new oil compatible with R134a added, the seals if in good condition should be okay.
Iso-butane as used in refrigeration should not be used as it is highly flammable. CFC's,HFC's & HCFC's are not.

[shadquattro]

Air Con. re-gassing

It's a common myth that refrigeration systems need re-gassing so often. The gas will last forever and only needs replacing if it has leaked out or part of the system has been replaced. If it has leaked out then the leak must be found and repaired before re-charging. adding gas to a system knowing it is still leaking is illegal.
However, car ac systems have flexible seals in them and can be prone to leaking, to greatly reduce this risk ac should be used every week for a few minutes to circulate the oil to keep seals lubricated. No problem with climate control as it will often be used to obtain a set temperature throughout the year.

Please note that deliberately releasing refrigerant gas is punishable by a £20,000 fine and 5 years inside (if caught and convicted) It can also be dangerous as the gas is at high pressure and boils at around -40C which can cause frostbite.

[Rob W]

That makes sense,fridges dont need topping up,i know there are various differences but principle is the same ???

[Rob W]

MY A/C

[Rob W]

I will start again My A/C went awol 2day in traffic,started to smoke from it radiator then switched off a minute later as i had arrived where i was going,when i switched on again it just screeched loudly???????
It was only gassed about 5-6 weeks ago,please dont say they put the wrong gas and its done the seals or i will feel a law suit comin

[shadquattro]

Rob AC

I take it the smoke is from the radiator/condenser area,was it the fan belt slipping as this will cause smoking and screeching. Can you see the complete compressor clutch assembly turn,does it click when it engages. I don't think the gas would have caused a problem. Is there any trace of oil where a leak may have developed on a union/join. Have you taken off the plastic cover over the rad and can you see where this smoke is from. Does it smell. Refrigerant gas and oil smells like oil and glue mixed, is the smoke oil and gas vapour. Hope this is of some help.
Michael.

[Rob W]

I was thinking about the belt slipping after reading about Martyn's stripdown,as the sound could well have been that,but the smoke very little actually,when i stopped and looked under the bonnet,i would say it looked and smelled like a very small oil leak,but not engine oil.I couldnt actually see where the smoke was coming from,it was very thin wisps from that general area,the car runs fine with the A/C off.
I am going out into the HEAT to investigate more shortly.

Thanks Michael

[s2driveruk]

Back to the R12 conversion again...

Guys,

Ok, finally decided that i need to get mine regassed and went to Whites Audi for a price £115 all in sir. So i asked what gas it had in as I wasn't 100% sure. They checked the top of the aircon radiator and they spotted the R134a marking and said yep, newer version.....excellent I thought.

Then I thought well if its the later gas i will check and see if i can do it cheaper. A well known local garage said £75 for a regas, deodorise and add in a neon gas to spot leaks etc. Excellent, even better at that price.

Then I thought, might be good for them to check and be doubly sure that I do infact have the later version as you can never trust and Audi dealership it seems on these beasts. Low and behold my car infact has R12.......fook.

Not a problem they tell me. I need to get the r12 removed as they don't have the older style connectors (they pointed me to a local garage that can do that) and then they can leak test, recharge it with the newer gas and some new oil from the US.

Now I read through the previous postings and I am totally not sure what the state of play is on this. They seem totally confident that the conversion requires no new seals or anything else, no change of drier for compatibility etc etc etc, just the use of a new oil and a recharge and away I go - £150 for the job. They have done this before without any problems and the guys I spoke to seem to know their stuff.

Whats the state of play on this? I am tempted to do this unless anyone is 100% sure that this is going to cause problems.

Cheers,

David :confused:

[s2driveruk]

Rob,

I knew I would find the details in the end of that place in Kent:

http://www.powerbase-auto.co.uk/retro-fit.htm

Cheers,

David

[Rob W]

Thanks Dave you are a bit of an A/C yellow pages are'nt you.

[shadquattro]

Air con

David,

If your car has R12 gas then the charging connections are standard 1/4" sae, this is the charging hose size as used by every refrigeration/air con engineer, if the garage doesn't have this connection then they are probably not fridge engineers.only car mechanics with car ac knowledge. £150 seems excessive for a recharge plus oil.
Trade prices are 1kg R134a £10
Oil 500ml £5
Ultra violet dye £5
Labour and expertise £40 per hour
Deoderise fine mist sprayed into vents £2?
Approx time one and half hours max.

Seals should be no problem. Try a refrigeration company from yellow pages rather than a car ac man. They may help for less.If in Norfolk contact me and I will help.
Michael.

[s2driveruk]

Hi,

Cheers for the reply. They charge £75 for a standard regas for r134 compatible cars and a further £75 for doing the conversion from R12 to the later stuff. I thought £150 wasn't too bad but looking at those prices maybe i'm wrong. Audi wanted £115 just to regas, clean and add neon leak dye which is steep.

From what these guys were saying they just don't deal with anything to do with R12 (i.e. recovering the gas) so they can help once the system has been evacuated of the gas then they have all the right connections etc etc. However will the new gas require a new connector or will the standard one be retained.

I'm in Hants so not quite round the corner from Norfolk but for a good job done i might point my car in that direction

Cheers,

David

[shadquattro]

conversion

the connector will not need to be changed,
these people should have a recovery machine to be able to service /repair the systems , the conversion is simply recovering the existing gas , flushing out the old oil,vacuuming the system,adding new oil and recharging with 134a the only thing thats different from charging the system is the removal and replacement of the oil . if the history of the system is unknown it could have 134a already with or without removal of the oil i doubt wether the a/c guys would know which gas it has as they would assume that the label they have seen is the gas it contains but this is often not the case

[s2driveruk]

think thats half the problem with A/C, nobody seems to know whats in there before they start......

David