Which oil for my aircon?

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Which oil for my aircon?

Postby Jared » Tue Sep 02, 2014 4:07 pm

I have ascertained that my old XJS aircon was converted to R134 and has some R134 gas left in it and has passed a pressure test.
Before we go ahead and re-gas can anyone tell me what oil I need to use with this system?
Is there a recommended oil for old converted aircon systems or do we just use standard oil.
Mine is an '88 V12 with the MK3 Delanaire compressor.

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Re: Which oil for my aircon?

Postby ptjs1 » Tue Sep 02, 2014 4:58 pm


R134a uses a completely different oil to R12. This is one of the reasons why you can't just change the gas to convert from R12; you have to have a neutralised system in order to stop R134a reacting with the residual oil.

Whoever, you get to do the evacuation, vacuum test then recharge will do it with a machine which is specific for R134a and mixes the correct oil. No compotent aircon fitter will get the wrong oil, don't worry!

1995 XJS 4.0 Convertible
1980 XJ-S Pre-HE
Jaguar 4.2 Supercharged engine (but not with a Jaguar body..)

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Re: Which oil for my aircon?

Postby almcl » Wed Sep 03, 2014 9:53 am

There is more than one type of oil available for R134a filled systems, PAG (polyalkylene glycol) which comes in two varieties: PAG 1 and PAG 2. There is also POE (polyester oil).

There are several theories about whether all mineral (R12) oil needs to be removed from the system (good discussion in Kirby Palm's XJS help book) and whether the ester oil mixes with it. I've used POE in my last two rebuilds (brand name Estercool) but was rebuilding an empty, clean system so didn't have to worry about this.
Al McL
'93 XJS 4.0 - '05 X type Est 2.0D - '13 XF 2.2D Sportbrake

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