The A/C in my '89 300CE blow somewhat cool, but I'm pretty sure that it needs to be recharged. What is the best way to get it working well again? Some say that R134A would decrease system performance, but I don't think R12 is available anymore at any cost. How about those R12 system compatible replacements? Do I need to replace any components when upgrading? I suppose it would be worthwhile to check for leaks considering the age of the components. What should an average retrofit to R134A cost?

I believe r-12 is more available recently than it's ever been. Take the 609 course online and go buy some on ebay.

EDIT: Just noticed you are in Canada, don't know how the rules work up North.

__________________
BENZ THERE DONE THAThttp://www.peachparts.com/shopforum/...c/progress.gif
15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)

My '83 380sel had already been converted to r-134a before I bought it. Performance was Ok, not great. On a typical summer day the air coming out of the vents would be around 50 degrees fahrenheit when the car was moving, a few degrees higher is stopped. I converted to Dura-Cool, http://www.duracool.com/, one of the hydrocarbon refrigerants, and it was better, 42-45 when moving, about 50-54 when stopped.

There's a lot of controversery regarding the hydrocarbon refrigerants, but my experience has been that they cost less, work better and are easier to use as they don't require an oil change. If you go to r-134a from r-12 you'll have to flush the mineral oil out of the system and replace it with pag or ester oil. The hydrocarbon refrigerants are OK with any of those oils. In any case it's a good idea to replace the receiver/dryer.

__________________
2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

I've tried several refrigerants over the years, and refrigerant substitutes. I've noticed that if it's an original R12 system, then R12 will work heads and tails better than anything else, period. The other options will be varying shades of "not as bad as R134". The only thing I've encountered that even comes close is a product called "Freeze 12" that gets pretty close. But R12 is still the cat's meow as far as I'm concerned.

I have had a couple W126's, both of them the previous owner had done the R134 conversion, and on both of them I went back to R12. There must have been a good 20F difference in vent temps both times, no exaggeration whatsoever.

I guess the main factor is, I live in Florida where summer is 2/3rds of the year and it's normally 98 degrees. I can't live with vent temps in the 50's, that would be miserable. With a properly functioning R12 system in my W126, the car could make itself uncomfortably cold inside, I'm talking ambients easily in the low 60F's, on a 100F day and at a dead stop. With 134, and with most of these "alternatives" you'll be lucky to see 50F vent temps.

The only one I would recommend would be Freeze12, but if you live in a hot climate just bite the bullet and pay the money and go back with R12.

For those in Hot/humid climates, the a/c system can be modified to work more effieciently by simply changing to a lower coolant thermostat, lowering the A/F ratio to 40%, and changing the aux fan to run on high vs low via a relay, using the same high side pressure switch.

__________________
A Dalton

never heard of the thermostat trick , Arthur. Good call.

__________________
1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

I like that trick of rigging the aux fan to run high instead of low

I don't understand how changing the thermostat and the AF ratio will effect heat transfer at the condensor. Please explain?

Thanks

I prefer R12 also but one of the problems recently, if you don't do the job yourself, is finding a shop that still has the R12 recycler. Many have disposed of them because they get so few calls for their use now. R12 should be readily available. If someone tells you it costs $100/pound, run away as fast as you can and find another shop that isn't trying to rip you off. My neighbor has a commercial HVAC business. He collected quite a bit of the R12 a few years ago during conversion jobs. He said you can hardly give the stuff away now. I have an adequate supply that was purchased legally before the law changed. Should be enough to keep my cars cool as long as I will be around!

You don't even have to worry about recycled R12. It's still produced in mass quantity in China and parts of Europe.

It's easy enough to get, I've never had any problem ordering it online with a simple sales tax license. Just order it "for resale", report it on your ST return, and then "sell" it to your mechanic for $1. You get a tax loss, and the transaction is perfectly legal and doesn't require a refrigeration license to complete the order (at least in my state).

If you were less ethical, you could of course just recharge your own car with it. While technically illegal, I doubt the EPA has any spies in the bushes in your back yard watching you. The chances of getting caught would be zero. IME, the rules/restrictions on this stuff have become less restrictive over the past several years, mainly because people have figured out ways around things. It's almost back to how it was in the early 1990s before R12 became a real hassle.

Banning R12 was just a political thing. Actually, R12 released (leaked) into the environment had less than a 1% effect on the ozone layer. Just like global warming. There HAS NOT been an increase in the average earth temp. for the past 12 years. Regionally, you will always see temp. variations but none globally. In addition to that, there has been very little sun spot activity for the past 12 years - a phenomena thought to be related to a cooling off process for the earth. Time will tell.

My 560SEL is running R134 and is acceptable in the Las Vegas oven period (summer) only because I removed the engine fan and put in a dual electric fan setup on the radiator. That made a significant difference.

One of my SECs and a friends 560SL are running R12 and I keep them cool by using R290 (propane!) as the topping off refrigerant. When those two cars get a little low on refrigerant and don't cool acceptably well, I add a little R290. R290, as y'all know, is used in Japan and the EU as an automotive refrigerant, and is MORE efficient than R12, plus is completely compatible with R12 seals and lubricants. It costs me around $2.00/Lb at the local hardware store.

Be Cool,
Mike R.

__________________
There is a very fine line between "hobby" and "mental illness."
FrankenBenz: '87 560SEC with an '02 cammed LS6 and custom 4L60E.
Bling: '87 560SEC, ported/polished, lowered
Lisa: '87 560SEL, lowered

Under hood ambient and there is passive heat exchange between the rad/cond.
Another thing is to leave the botton engine panel ON...you are not Channelling the airflow w/o it.

__________________
A Dalton

Does your 89CE have a 15 or 17 cc compressor??

Performance on W124 depends heavily on the circulating switch/diaphram being functional. If you're pulling all outside air- performance will be dismal. Make sure you set it to circulate!!!

Check the charge on the site glass. Perfect charge you see just a hint of bubbles when the expansion valve moves, then they disappear(change in pressure). Look at connections for oil and hoses for potential leak points. Unfortunately, the evaporators can be leaky...

These W124's have the old tube/fin evaporators which tend to be poor at conversions to W134a. For any system conversion, you need to have the fan on when ever the compressor is on UNLIKE R12 systems. Factory R134a have 2-speed fans. Some ppl put parrallel flow condensors etc.. lots of work and $$.

M

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!

__________________
2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

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