I know the AC in the 200's leaves much to be desired. I own a 87 and I know this for a fact. Did the AC system change at a later year that allowed for better performance? If so what year was this? Thanks

Don't worry about the change to 134. It is not widly known that 134a needs more pressure and really isn't very efficient either. Switch over to hydrocarbons. These refrigerants are much more efficient, you only use about 1/2 the amount that is in there now,it works with less pressure and you will get better gas mileage when you use it. Here is another plus, most all the seepers, you know, the ones that need charging every year, will never need charging again because the molicules are much larger and they won't leak. I put it in my 88 240 and I don't run my system on high anymore. Last summer I drove from Pa. to Wa. and on the way home, going through So. Dakota, it was 117 degrees and we had the air on low and the thermostat wasn't even all the way up and we were cool and comfortable. It also is very cheep and is envirmentally safe too. To charge your car it will cost you only about ten bucks or less. Take out the freon and put this in, there are no changes to be made. Anyone can get it, there are no lisences or permits needed. Do it yourself and save.

Wayne You stated "switch over to hydrocarbons", cpould you put a brand name on this?

Look up "hydrocoolonline.com" and read! All your questions will be answered there. If not and you want more info, contact me again and I will help in any way I can Wayne

Yes: 1991.

In 1993 it has 134a. The 91/92 models are easily converted and have good performance with that refrigerant.
--
chris herbst, near chicago

Hi Chris, I find your posts to be very informative and level headed. I've got a 92 245 and I was thinking that it might be due for a recharge this spring. How difficult is it to convert from R12? Is it a do it yourself project, or should I take it to a shop? Also, how much are parts vs. the cost for a shop to do the conversion? I'd hate to mess things up trying to safe a few $.

If you are handy and careful, you can do a good job.

The proper conversion consists of:

Changing all the system O-rings (use ester oil on the seals)
Removing the compressor and draining all the oil from it
Removing old fixed orifice tube and reinstalling a new one
Flushing the parts that you can effectively flush
Replacing the accumulator
Adding new ester oil
Vaccuming the system
Charging with the proper amount of R134a.

Most of the conversion is simply mechanical work. Taking out the compressor, changing the O-rings and Fixed Orifice Tube (FOT). Cleaning, reassembling, etc.

The tough part is vacuuming the system (need vacuum pump) and charging with the proper amount. You have to be very accurate (or err slightly on the low side) when charging with R134a. R12 is much more forgiving with respect to overcharging.

At a shop, the conversion might cost $300-400 done properly. Volvo makes a COMPLETE kit (but you still need to buy compressor O-rings for some reason) and it includes everything you'll need in one box. The kit is "approximately" $75, which will vary on where you buy it.

The 92 is easy to convert. No new evaporator necessary. Not much of anything new. The only thing I like to do with the 91 and 92 models is to jump the pressure switch on the high side expansion pipe (right side frame rail on a little J-shaped pipe). By jumpering that wiring harness and sealing it up permanently to keep moisture out, the electric fan in front of the condenser will run at any time that the A/C is on. It helps to keep the pressures in a more manageable realm.

It is hard to estimate the shop cost. It should be around $200-300 to do properly. If they're doing it right, it will take a few hours. If you want to save some money, though, you can do the conversion and then have the system vacuumed out and charged. Or do it yourself--rent the vacuum pump or something. The only thing to watch out for, is if you do the conversion and then have someone else vac & charge it, you should do it soon after doing the parts conversion. Otherwise the accumulator will acquire too much moisture. And moisture is disastrous, especially in R134a systems.

The only other pitfall of the conversion is that periodically the compressor shaft seals will leak. Usually this isn't a problem with the DK compressors on the 240 series. They tend to hold up very well to conversion. As long as the system isn't overcharged or under-oiled, and it is performed with some care, you will probably have a very solid A/C system. And it will perform well also. While R134a isn't quite what R12 is, as a refrigerant it is still a decent performer.

Also, the 700/900 FAQ on this site has a very good section on A/C. The 700/900 system is fundamentally the same, with the exception of the car it is installed in, the location of certain components, and the refrigerant capacity.
--
chris herbst, near chicago

Thanks Chris. I'll take a look at the FAQ. I'm a little scared to tackle it myself. But I was also a little scared the first time I did my timing belt. This past summer I looked at a few of your old posts and I jumped the pressure switch so that the electric fan runs all the time that the AC is on. Good tip. I'll post in a few months to let you know how I made out.