I know this subject has been beat to death, but I haven't been able to find an answer I could understand to this specific question, so thanks in advance for your patience.

Just bought a '91 240, 171k miles, built with an R12 A/C system. It cools well but short-cycles at speeds above idle, like 3 seconds on-3 seconds off, most noticeable under increased loads like a hill. I've been trying to find the "spyglass" that other posts have described to have a look at the R12 level, but I can't find anything like that in the position described (to the right of the radiator on the pax side, nor on the left.) What I do see, behind the pax wheel well, is a tall round tower, black on the bottom, silver on the top, with three big hoses running out of it. At least one outlet connects with the compressor through a thick rubber hose. There are a couple of fairly large valve-type covers that unscrew. There are no stickers anywhere under the hood to indicate that a conversion to R-134 was done. The tower does look newer than most of the rest of the engine compartment.

What do you think? Also, if it is a conversion, is there no spyglass like in the R-12 system, or is it somewhere that I'm not seeing?

Scott
'91 240 171k, '92 745t 240k

Hi Scott,

I doubt very much your 91 has been converted. The obvious place for the sticker is on top of the accumulator - that tower of silver with the three pipes coming out. The old receiver/dryer you are looking for, with the sight glass, was done away with for 91, as well as the TXV inside.

Your system is ideal for conversion compared to the older ones. The evaporator won't need changing; you already have the fan in front of the condenser. Much easier job.
--
Art Benstein near Baltimore

Never put both feet in your mouth at the same time, because then you won't have a leg to stand on.

What you have is the later style AC system that kicks butt! The cylinder or tower you are referring to is the accumulator.

Now, to figure out if it has been converted or not. On the U-shaped pipe that exits the passenger side of the accumulator and runs to the firewall, there is a fitting that sticks up, here is the easiest way to identify the refrigerant.

If the fitting has a metal threaded cap on it, it is R-12.
If the fitting has a plastic threaded cap on it and it says max 6Nm, then it is R134A.

This system is much more efficient than the expansion valve based system used up through 1990. If your system is still R-12, FCP groton does sell a conversion kit for less than $100... it includes the oil, O-rings, new U-pipe, and accumulator plus a few other items.

I would highly recommend flushing the system if you are doing a conversion, you will also need to drain the compressor and refill it with the new oil. Finally, replace the orifice tube. Then vac it down and re-charge the system. NOTE: This is an oversimplification.

jorrell
--
92 245 250K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

The cap appears to be metal and has only a serial number and a Volvo part number on it. So I guess it's R12. Oh well, it was too much to hope that the PO had already spent the money. It still cools well, I'm just concerned about the compressor short-cycling (not at idle, only at moderate speeds.)

I converted my 1992 240 to R134a last summer. I purchased the Volvo made conversion kit from FCP Groton. I had the system evacuated at a local garage to remove what R12 was still in the system. I then followed the directions in the kit (replaced the o-rings, orifice, installed new accumulator, drained etc.). I was amazed how simple it was to do, since I had never done any work on an air conditioning system before. After I was done, I took the car back to the local garage where they filled the system with R134a and checked for leaks. Including the money I spent buying the conversion kit from FCP Groton, it cost me almost $200 to complete the conversion. So far this summer the system continues to cool well. It was 98 degrees here yesterday and I was very comfortable on my commute home in the afternoon.

Best Wishes.

13