br1anstorm
NAXJA Forum User
- Location
- United Kingdom
I have a 1993 XJ 4.0 litre. The a/c system has been empty for about a year after the condenser (or a hose connection to it) developed a leak. My plan was - and is - to overhaul and convert from R12 to R134a.
I have been stirred into action by the fact that my radiator has just suffered a leak too. Since I have to replace that, I thought I'd do the a/c at the same time.
I've read several threads on the conversion process. I know the system has to be cleaned and flushed. But a few questions remain unanswered.
1) what parts to replace? I have new condenser and new receiver/drier. I hope and believe I can continue to use the original compressor. Do I have to replace the expansion valve as well, or can I get by with the existing one?
2) hoses (aka "lines"). There are four. I plan to replace the two that connect to the condenser, because on the old ones, the alloy-pipe sections by the radiator and condenser are pretty rusty. Can I retain and re-use the other two lines, which connect between the expansion block and, respectively, the compressor and the receiver/drier?
3) hose options. There appear to be different part nos for the hoses between 1993 models (in which R12 was used), and 1994 models (the year R134a was introduced). The latter are the same 'shape' but a couple of them have connectors or valves fitted like spurs. Will the 1994 parts fit my 1993 vehicle? And are these 'spur' connectors specifically a feature of R134a installations?
4) compressor connections. There appear to be valves on the top rear of the compressor, with what look like open/close controls. I found an old thread here in which ParadiseXJ and 90xj06 sort-of explain how these work. They seem to be rather peculiar, with three positions. Does the system have to be recharged via these valves, or via the 'new' valves/connectors on the new hose lines?
5) draining the compressor, and oil change. R12 systems use mineral oil. I believe R134a systems use a different oil (PAG?). How exactly to flush or empty the compressor? Is it necessary to de-mount it and have the oil pour out of the hose-connector sockets? Or does the oil have to be sucked out somehow, or the compressor purged using compressed air or something?
6) capacity/amounts. I haven't yet checked how much refrigerant or oil is required. I read somewhere that for R134a you need a bit less: about 80% of the amount of R12 . And how much of the new (PAG?) type of oil?
Those are the questions that have occurred to me so far. Answers, and any other wise advice, would be appreciated!
I have been stirred into action by the fact that my radiator has just suffered a leak too. Since I have to replace that, I thought I'd do the a/c at the same time.
I've read several threads on the conversion process. I know the system has to be cleaned and flushed. But a few questions remain unanswered.
1) what parts to replace? I have new condenser and new receiver/drier. I hope and believe I can continue to use the original compressor. Do I have to replace the expansion valve as well, or can I get by with the existing one?
2) hoses (aka "lines"). There are four. I plan to replace the two that connect to the condenser, because on the old ones, the alloy-pipe sections by the radiator and condenser are pretty rusty. Can I retain and re-use the other two lines, which connect between the expansion block and, respectively, the compressor and the receiver/drier?
3) hose options. There appear to be different part nos for the hoses between 1993 models (in which R12 was used), and 1994 models (the year R134a was introduced). The latter are the same 'shape' but a couple of them have connectors or valves fitted like spurs. Will the 1994 parts fit my 1993 vehicle? And are these 'spur' connectors specifically a feature of R134a installations?
4) compressor connections. There appear to be valves on the top rear of the compressor, with what look like open/close controls. I found an old thread here in which ParadiseXJ and 90xj06 sort-of explain how these work. They seem to be rather peculiar, with three positions. Does the system have to be recharged via these valves, or via the 'new' valves/connectors on the new hose lines?
5) draining the compressor, and oil change. R12 systems use mineral oil. I believe R134a systems use a different oil (PAG?). How exactly to flush or empty the compressor? Is it necessary to de-mount it and have the oil pour out of the hose-connector sockets? Or does the oil have to be sucked out somehow, or the compressor purged using compressed air or something?
6) capacity/amounts. I haven't yet checked how much refrigerant or oil is required. I read somewhere that for R134a you need a bit less: about 80% of the amount of R12 . And how much of the new (PAG?) type of oil?
Those are the questions that have occurred to me so far. Answers, and any other wise advice, would be appreciated!