Automotive Air Conditioning Information Forum (Archives)

Provided by www.ACkits.com

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

Converting Mercedes 560SL 12 to 134

David R. on Tue March 30, 2010 9:16 PM User is offline

Year: 1986
Make: Mercedes
Model: 560SL
Engine Size: 560
Refrigerant Type: R!@
Country of Origin: Germany


I have a 1986 Mercedes roadster 560SL that I want to convert from R12 to 134. When the AC was in good working order it struggled to cool on 90+ temp days with R12. Now that the system is open I want to convert to 134. How is the best way to do this? It has a Nippondenso compressor and the org. condenser. All advise wiil be much
appreciated.

DRR

bohica2xo on Wed March 31, 2010 3:02 AM User is offline

If you think it struggled with R12...

It will take a substantial bit of work to improve performance with 134a. You will need an upgraded condensor, and you will need to upgrade the airflow across the condensor as well.

There is not a lot of room to make those changes in the MB's.

80's vintage euro cars have an A/C system that provides a "gentle cooling" that is most appropriate anyplace you would be quite comfortable with the windows rolled down. It's main function is to make the car quiet at highway speeds on a 20c day.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

David R. on Wed March 31, 2010 11:14 AM User is offline

Thanks for your suggestion, do you have a recommendation for the condenser? The OEM is about 22.25 X 17X1. I can get a parallel flow but it is only 22.5X14. Will the efficiency make up for the smaller size?

DRR

HVargas on Wed March 31, 2010 12:04 PM User is offlineView users profile

The efficiency will help make up for it but you still have to be able to get the air to flow across it and that I think is what he is referring too. You may have to mount a fan on the condenser to help with airflow. We do have an 18"x22" available and that would be just a touch bigger than your current one but if you have the room I would definitely recommend it. Once the condenser is installed you will need to fabricate the ends of the lines that connect to the factory condenser to thread onto the new one. From there you will need to flush out all of the lines, evaporator, replace the expansion valve and receiver drier and flush the compressor with BVA Auto 100 oil to remove all of the mineral oil. Then you can reconnect everything, replace the R12 valves with R134a service valves and begin to charge the system to 75-80% the R12 capacity.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: Arizona Mobile Air


Edited: Wed March 31, 2010 at 12:06 PM by HVargas

bohica2xo on Wed March 31, 2010 3:23 PM User is offline

Adam, that is exactly what I meant. A big increase in airflow will be necessary to take advantage of the condensor you recommend.

The V8 SL's are tight in the engine bay. Increasing air flow can be a challenge. Some of those cars had issues with high underhood temps - they even installed a small heat exchanger in the refrigerant suction line to cool the fuel return. That was to keep the fuel from boiling...

You will need to add a fan, and make sure the mechanical fan is doing everything it can to move air over the heat exchanger package. Be sure that the airflow through the heat exchanger stack is not bypassing the condensor on the way to the radiator.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.