You need to do a check of your system pressures. Could be that the freon has leaked out enough that the pressure is too low and the compressor won't engage.

Thanks for the advice regarding the different options. It appears that I will have to upgrade to R134A since Canada's regulations are a bit different compared to the US. Hopefully, the system will cool better than now. Since summer is not as intense up here, I'm hoping that an R134A conversion brings good performance. There is one product that is sold legally here under the name Red Tek 12A that is supposed to work as well as R12. Has anyone heard of it?

That's exactly what you should NOT do!

R12 is the way to go! It will work 10X better than R134a. You can kinda/sorta make 134 work almost as well as R12 by adding extra electric fans, a bigger evap, etc., but why bother? Just go with the R12. It is more money, but it's worth it.

If you don't go with R12, try Freeze12 (you can buy it online). But don't go with 134a.

Who is going to recharge R12 into the system? I don't have the tools or qualifications to do it myself so an independent shop would be doing it for me. You cannot buy it without getting a special permit or license and I doubt the shop would willingly want to install R12.

There will be someone in your area who deals with R12.

Get the phone book out and call auto repair shops.

Or, I know they're always waaaaaaaaaaay expensive, but the dealers can usually do it also. Trust me, though, it's well worth it.

FYI,

Freeze12 is 70-90% r134 and 10-25% HFC 142b, according to their own MSDS.

I've been using hydrocarbon based refrigerants for years, Dura-cool, enviro-safe etc. and have been very pleased. I never heard of using R290 before. Do you buy it the same way I do for my home barbeque, by the 20 lb. cylinder? If so what kind of hookup did you use to go from the 20 lb. cylinder to your gauge/charging set? I'd love to know.

One of the vehicles I changed over was my 94 Chrysler which came from the factory with r134a. Performance was marginal until I charged it with Dura-cool, now if blows at 36 degrees!

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

This is just my own personal experience, so take it for what you paid for it.

But in my observation (in original R12 systems in the W126's) Freeze 12 works about 75% as good as R12 while R134a by itself only works about 50% as good as R12.

Neither is as good as the real thing, but Freeze 12 (must be whatever difference the 142b makes) is still a lot better than putting in 134a by itself.

I'm a little scared of hydrocarbon refrigerants. Not sure if this is just scare-tactic hype, but read this: http://www.theautochannel.com/news/2005/04/25/047878.html

I did a lot of homework before deciding to go the hydrocarbon route and finally decided all the hype was basically scare-tactics. Remember, R134a is only made by one company, Dow Chemical, and they have plenty of muscle to scare folks with. Hydrocarbon refrigerant is widely used, throughout the world. Plus, adding 12oz. of flamable stuff to a car already carrying a hundred pounds or more of REALLY flamable stuff (gasoline) seems like a pretty low risk.

The bottom line is that it's cheap and works really well, even improving the AC in my Chrysler that came from the factory with R134a. Vent temp with R134a was high 40s to low 50s, now it's mid to high 30s.

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

one more thing that you guys should all realize.the evaps in 126 cars had a certain amount of epoxy on the u tubes at the ends and 134 molecules being smaller than r12 has managed to find small enough holes and then create bigger ones as the epoxy gives up.in short unless your 126 has had the evaporator replaced[or 124's]put freeze 12 in at your peril or at least plan on replacing the evaporator.[same goes for 134 conversions]

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

Update:

I have found that A/C performance is not as bad as I once thought. At highway speeds it is ice cold with an outside temperature of 90F. In the city and at lower speeds the performance seems to be not as good and it is noticeably less cold. Should I always be hearing the fans kick in when I turn the A/C? At times I hear the roar of the fans when accelerating but at other times I don't hear anything. At idle if I turn the A/C on I hear the A/C compressor engage but I usually don't hear any fans kick in. Is it possible that the fan and switch are not functioning correctly? I'm also considering cleaning the front condensor to see if that helps performance at lower speeds.

If you have high ambient temps and no low fan at idle/traffic conditions, then you have to check the low fan circuit by jumping the high pressure switch at the drier..if Yes w/jumper, then the suspect is slightly low refrigerant.

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A Dalton