Air conditioning upgrades, modernisation

Hello all,

I am looking at the 45 year old A/C condenser / radiator on my workbench, with all the road grit, squashed fins etc… and i am not sure my best option is to put this thing back in the car.

This Jag has to have A/C (California), and respect of originality is not a concern.

I wonder what others have done and what reasonable options are available.

Thank you.

Dunno which model you have, but if the system originally had R-12 refrigerant, many would recommend taking this opportunity to upgrade to a two-pass condenser designed for R-134a.

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Google “Fen Air” They are an outfit in the UK that sell A/C upgrades for the classic Jags.

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The system is still totally original.

Would the upgrade you mention (i have to educate myself) require replacing the whole unit inside the car?

Nope, just the condenser. If you go with a conversion to R-134a – which I recommend – you’d also want to replace the expansion valve with one designed for R-134a. But really, you don’t have to do that, it just makes the A/C work better. You don’t have to upgrade the condenser either, but using R-134a requires more heat transfer lest the pressures run away and blow something, so if you use the original condenser you’d have to make sure the fans are providing plenty of airflow through it – probably more than original. Like I said, if you have to replace the condenser anyway, go for the uprated one.

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This is very useful, thank you.
So, if evaporater, compresser, and hoses don’t leak and work ok, i can just simply replace the condenser, put R134a in the system and be fine?? Cool (…)!

Replacing the expansion valve sounds like a good idea.

I suspect that all seals will need replacing too, right?

I fitted the car with a 2,000 CFM electric fan, working on a 91°C thermoswitch. Does that sound appropriate for the AC to work.

Also, I am thinking of deleting the fuel cooler thingy, I am wondering if it actually does anything at the best of times…

This video is useful. It is for the V12, but seems very applicable to the XK engine version.

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I probably need a new receiver-drier too…

I took my condensor to a radiator shop and had it cleaned. I bought a new drier. I am set for R134. But, have never charged the system.

There is a teeny screen at the Ronco that should be replaced or even omited.

Lines and evap should be flushed. I failed to do that.


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Agreed! I had a problem with that screen being clogged on my Corvair factory AC. But to clarify, I believe it’s inside the input line to the expansion valve, not the Ranco switch (which doesn’t come in contact with the refrigerant)?

The deal with O-rings is another issue that has bred many a myth. The O-rings that came in the car are perfectly compatible with R-134a. However, O-rings swell a little bit with exposure to R-12 and swell a little bit less with exposure to R-134a. Hence, a tired O-ring that was just barely sealing with the R-12 might start leaking with the R-134a. What’s more, some of the grooves the O-rings fit into may have been machined to allow the swelling with R-12, so they fit a bit loose with R-134a. When swapping to R-134a first became popular, you could buy O-rings made of the same material but just a hair chubbier to make up for the reduced swelling. They were typically coated with green chalk, leading some to think the rubber itself was green, but you could wipe the chalk off and see the black O-ring underneath.

As a general rule, none of this is a problem. You can just install new standard O-rings and it’ll seal up just fine. You can leave the old O-rings in there and it will probably seal up just fine. But a shop that has to make a profit doing this job will always figure upgrading everything in their quote just in case they have to do it all to prevent leaks.

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Yes, but remember you’ll need that fan to run whenever the A/C compressor is engaged regardless of the thermoswitch.

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Always replace the receiver-drier whenever the system is opened up.

It’s been a minute, but IIRC the replacement expansion valve I installed came with a conical inlet screen that stuck about two inches into the pipe that connected to the expansion valve. Really nice and essentially unpluggable. The expansion valve that came out had no inlet screen at all and had been fouled by a bunch of crud coming down the line when my receiver/drier had failed internally and dumped its guts into the line. I dunno how common that failure is, though.

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What is “Ronco”?

I think it’s “Ranco”, actually. It’s a thermo switch with a sensor bulb on the end of a tube that is positioned behind the evaporator, and disables the compressor when it gets too cold to prevent the evaporator from icing up.

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Emphatically second that, Kirbert - it’s a must…

xj6 85 Sov Europe (UK/NZ)

This is what I did to my XJ6 in 2016. You will have to suffer though the trip to Tasmania story. New evaporator, condenser, Sanden compressor, dryer etc. It’s really cold. Sanden is a rotary compressor and much more efficient than the original York. Naturally, many would not go this far! Paul.

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Woops, here’s the link.

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