AIR-CON Cooling

[headcover]

Hi.. my air-con is not cooling as cold as it did last year,  Is it a simple case of getting it re-gassed etc or is there something wrong??? any advise is welcome..

[melinx]

It may be that it needs re-gassing, my Diplomat does not get anywhere near as cold as the Vectra, but I believe that it is working to spec. and is showing correct working gas pressure.
If you can put a digital thermometer in the face air vent and set the air con to recirculation, you should be able to get down to about 12 to 14 degrees C below the outside ambient temp. if outside is above 20.
Something that does not help the air con is if the temp. control is not totally closing off the hot water,
on mine, with the air con off and temp. control at minimum the thermometer will read a couple of degrees above outside ambient.
If it does need re-gassing, it will almost certainly have to be changed from R12 to R134a gas
( unless, of course, it has already been done ) that will need new adaptors, the system pulled down to vacuum and held there to check for leaks and then a charge of PAG oil and R134a.
Some places will want A LOT OF MONEY for this, but I had that done for about £50

[headcover]

It may be that it needs re-gassing, my Diplomat does not get anywhere near as cold as the Vectra, but I believe that it is working to spec. and is showing correct working gas pressure.
If you can put a digital thermometer in the face air vent and set the air con to recirculation, you should be able to get down to about 12 to 14 degrees C below the outside ambient temp. if outside is above 20.
Something that does not help the air con is if the temp. control is not totally closing off the hot water,
on mine, with the air con off and temp. control at minimum the thermometer will read a couple of degrees above outside ambient.
If it does need re-gassing, it will almost certainly have to be changed from R12 to R134a gas
( unless, of course, it has already been done ) that will need new adaptors, the system pulled down to vacuum and held there to check for leaks and then a charge of PAG oil and R134a.
Some places will want A LOT OF MONEY for this, but I had that done for about £50

Thank you for the advice my friend.. I have been quoted over £200.00 to change my air-con to fun on the new legal gas!!  Where did you get yours done.. It might be worth me traveling to get it sorted out...ta

[melinx]

I had it done at Central Subaru in Willenhall ( nr. Wolverhampton) 01902 636286 www.centralsubaru.co.uk
A good place for air con. gas and parts is Rabtherm in Aldridge ( nr. Walsall) 01922 743273
www.rabtherm.co.uk
Rabtherm sell to people who then put it on ebay at a considerably higher price !! the high pressure and low pressure port conversion fittings from Rabtherm are about £2 each

[melinx]

Something I need to correct ! When changing from R12 to R134a it is vital that you do not just inject PAG oil, it is incompatible with the oil that is in the system for the R12 gas, a special oil with neutraliser must be used, otherwise there is a reaction between them and a black 'gunge' is formed which will spell death for your a/c system.
Using that special oil (I've no idea what it is) when the changeover was done for me, my air con, system has been fine for 12 months now.

[melinx]

CHANGING THE CARLTON AIR CONDITIONING FROM R12 TO R134a GAS

It is no longer possible to legally obtain the R12 refrigerant gas originally used in the Carlton a/c system, ‘Drop in’ gas is available which is supposedly miscible with R12 but these gases are a temporary solution, however, if you do want to do it that way contact Rabtherm.
The proper solution is to change the system to R134a gas, which is also less ozone depleting.
The following contains some of the extensive advice and information that I have received from Rabtherm (mentioned in my earlier post)
It should be emphasised that it is illegal to vent R12 gas to the atmosphere and safety precautions should be observed (rubber gloves and safety goggles) if refrigerant gas gets squirted onto you it can cause nasty frost burns.
The part numbers and prices quoted are supplied by Rabtherm (price + VAT)
I recommend that the check and charge hose which has a pressure gauge incorporated is used (Part no. 26067 £12.00) this will enable you to keep an eye on the pressure over a few weeks and thus tell you if you have a system leak.
It will also tell you whether you are undercharging or overcharging the system; overcharge it and you may wreck your compressor.
The hose comes with comprehensive instructions and the gauge has colour coded segments indicating the correct working pressure ranges.
Assuming that you have no remaining R12 gas pressure in the system ( if the light on the a/c switch has not been coming on for some time, then the pressure switch has dropped out to prevent the compressor operating and the R12 has all leaked away)
Ideally, if there has been zero pressure for some considerable time, maybe caused by a bad leak, damp may have got into the system and it should be professionally vacuum pumped to boil out the condensation and leak checked.
The low pressure fitting is the one looking like a tyre valve on the top of the large silvery cylinder near the passenger side engine bulkhead.
It may be worth changing the high side valve also just to ensure that you have a new, non leaking valve there, you will find this one on the silvery pipe that runs along the top of the offside chassis member at the base of the wheel arch inside the engine compartment
Take off the plastic cap and remove the Schrader core and screw on the ¼” female adaptor ( blue cap low side ) ¼” high side female to male (slightly larger red cap)
Do not leave the valves open to atmosphere for any time or damp air will enter and water will freeze up in the expansion nozzle and stop the system working.
Make sure that you put the right conversion fitting on the low  pressure port because the check and charge hose will not fit the high side fitting.
If you have any doubt whatever about which is the low pressure port, do not attempt any of this procedure, injecting liquid gas into the high pressure side will at best wreck your compressor and at worst cause the can to explode and maybe cause serious injury.
THE HIGH PRESSURE SIDE OF THE COMPRESSOR MAY BE RUNNING AT 200 TO 300 PSI AND CAN GO TO 450 PSI BEFORE THE HIGH PRESSURE DISABLING SWITCH OPERATES.
Conversion fittings and the can containing the conversion additives (allowing the existing R12 type oil to work with R134a ) plus PAG oil, 55 grams of R134a and rubber seal conditioner come as a kit ( AC2135A £26.55 )
Two 340 gram cans of pure R134a will be needed ( 6312 £6.00 each )
Make sure that you read and follow the instructions that come with both the check and charge hose and printed on the cans.
A site with extensive air con. information is : - http://members.tripod.com/~jbabs714/autoac.htm

[headcover]

Wow..now thats what I call great advice.. Thanks.     I think I'll take my motor to them & get them to sort it out, I'd have a go myself but I think I'd end up killing myself..  Thanks again for all your advice..

[melinx]

Please note my edit warning of the 'high side' pressures in the air conditioning system

[CamInHead]

Something I need to correct ! When changing from R12 to R134a it is vital that you do not just inject PAG oil, it is incompatible with the oil that is in the system for the R12 gas, a special oil with neutraliser must be used, otherwise there is a reaction between them and a black 'gunge' is formed which will spell death for your a/c system.
Using that special oil (I've no idea what it is) when the changeover was done for me, my air con, system has been fine for 12 months now.

Is that just when it's converted or during subsequent recharges ?
We do recharges at our place and, while I doubt I'd ever see a converted car, I'd really like to know. 

[melinx]

Just when it's converted and then only if the original oil is left in.

If the system was stripped, flushed and the receiver dryer fully drained with new desiccant, it would not be necessary.

If the conversion was properly done and you are just replacing refrigerant that has leaked over time, pure R134a is all that is needed

[melinx]

Over 3 years now and it's still fine after following the conversion procedure I outlined

[melinx]

I had it done at Central Subaru in Willenhall ( nr. Wolverhampton) 01902 636286 www.centralsubaru.co.uk
A good place for air con. gas and parts is Rabtherm in Aldridge ( nr. Walsall) 01922 743273
www.rabtherm.co.uk
Rabtherm sell to people who then put it on ebay at a considerably higher price !! the high pressure and low pressure port conversion fittings from Rabtherm are about £2 each

Please note that Central Subaru no longer do air conditioning: Apparently, a place not far from them do it but they would charge about £50 for vacuum pumping and re gassing with R134a; no idea what they would charge for converting from R12 !

[diplomat2.6]

I think the special oil you refer to is called 'ester oil' or POE. It is available from CAS, for example. It is compatible with R12 and R134a and can cope with PAG and mineral oil. I was sold some by mistake for my wife' Volvo 850 which I'm doing a compressor swap on this weekend. The only problem is that there doesn't seem to be a choice of viscocities which may be a problem with compressors demanding thicker oil.

[Pedro]

Giving/receiving advice is awesome, what the forum is all about, but please note that Headcover was banned yonks ago!
He came back under different names, but his real name is David Ho/Neo/Kudos.

[melinx]

CHANGING THE CARLTON AIR CONDITIONING FROM R12 TO R134a GAS

It is no longer possible to legally obtain the R12 refrigerant gas originally used in the Carlton a/c system, ‘Drop in’ gas is available which is supposedly miscible with R12 but these gases are a temporary solution, however, if you do want to do it that way contact Rabtherm.
The proper solution is to change the system to R134a gas, which is also less ozone depleting.
The following contains some of the extensive advice and information that I have received from Rabtherm (mentioned in my earlier post)
It should be emphasised that it is illegal to vent R12 gas to the atmosphere and safety precautions should be observed (rubber gloves and safety goggles) if refrigerant gas gets squirted onto you it can cause nasty frost burns.
The part numbers and prices quoted are supplied by Rabtherm (price + VAT)
I recommend that the check and charge hose which has a pressure gauge incorporated is used (Part no. 26067 £12.00) this will enable you to keep an eye on the pressure over a few weeks and thus tell you if you have a system leak.
It will also tell you whether you are undercharging or overcharging the system; overcharge it and you may wreck your compressor.
The hose comes with comprehensive instructions and the gauge has colour coded segments indicating the correct working pressure ranges.
Assuming that you have no remaining R12 gas pressure in the system ( if the light on the a/c switch has not been coming on for some time, then the pressure switch has dropped out to prevent the compressor operating and the R12 has all leaked away)
Ideally, if there has been zero pressure for some considerable time, maybe caused by a bad leak, damp may have got into the system and it should be professionally vacuum pumped to boil out the condensation and leak checked.
The low pressure fitting is the one looking like a tyre valve on the top of the large silvery cylinder near the passenger side engine bulkhead.
It may be worth changing the high side valve also just to ensure that you have a new, non leaking valve there, you will find this one on the silvery pipe that runs along the top of the offside chassis member at the base of the wheel arch inside the engine compartment
Take off the plastic cap and remove the Schrader core and screw on the ¼” female adaptor ( blue cap low side ) ¼” high side female to male (slightly larger red cap)
Do not leave the valves open to atmosphere for any time or damp air will enter and water will freeze up in the expansion nozzle and stop the system working.
Make sure that you put the right conversion fitting on the low  pressure port because the check and charge hose will not fit the high side fitting.
If you have any doubt whatever about which is the low pressure port, do not attempt any of this procedure, injecting liquid gas into the high pressure side will at best wreck your compressor and at worst cause the can to explode and maybe cause serious injury.
THE HIGH PRESSURE SIDE OF THE COMPRESSOR MAY BE RUNNING AT 200 TO 300 PSI AND CAN GO TO 450 PSI BEFORE THE HIGH PRESSURE DISABLING SWITCH OPERATES.
Conversion fittings and the can containing the conversion additives (allowing the existing R12 type oil to work with R134a ) plus PAG oil, 55 grams of R134a and rubber seal conditioner come as a kit ( AC2135A £26.55 )
Two 340 gram cans of pure R134a will be needed ( 6312 £6.00 each )
Make sure that you read and follow the instructions that come with both the check and charge hose and printed on the cans.
A site with extensive air con. information is : - http://members.tripod.com/~jbabs714/autoac.htm

It's now 5 years since I converted the air con. system to R134a and everything is still working fine, although it has had a couple of top ups in that time, one of them from a can with leak sealer included in it.

Checking the system pressure this morning, I decided that although it was in the middle of the 'green' zone on the check and charge hose dial, I would treat it to a top up for the summer.

I drove out to my supplier (http://www.rabtherm.co.uk/rabdirect_bgas/r134a_refrigerant.htm) and bought another can only to find that the underbonnet temperatures had increased the system pressure to the top of the green zone

The cans are now 350 grams rather than 340 and come with 60 grams of multigrade PAG oil in the can which now costs £10

Edit : -

I've just noticed that the colour codes on the latest check and charge hose gauge is changed   the green and blue sectors are swapped on the latest one

[melinx]

I've been examining the fresh air intake for the heating/air con. system and it's obvious that the soft rubber strip that is fitted on the top of the engine bulkhead and seals against the bonnet is essential to keep hot air from the engine bay from entering the ventilation system.

If there are any large gaps at the ends, or the foam blocks fitted to the bonnet at that point are missing, it will radically reduce the effectiveness of the air con. system because of the hot air being pulled through the gap