Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: OldGuard60 on May 09, 2025, 20:06:45

Title: Convert A/C coolant?
Post by: OldGuard60 on May 09, 2025, 20:06:45

Should I convert my 71 280SL A/C from R12 or should I leave it original?

Title: Re: Convert A/C coolant?
Post by: BHap on May 10, 2025, 02:50:13

If it still works, I’d leave it alone. If you need to change the compressor, you may want to consider a Sanden conversion - and even then, you can keep R12. To make a change to R134 I think you need to change to a parallel flow condenser, install a new drier and flush the rest of the system. My 70 280SL has had the same R12 in it for the last 20+ years and still cools ok.

Title: Re: Convert A/C coolant?
Post by: Peter on May 10, 2025, 08:22:54

For conversion you als need to change the rubber hoses. So it's a mayor operation.

Title: Re: Convert A/C coolant?
Post by: OldGuard60 on May 10, 2025, 13:36:51

Thanks for that.  Do you know where I can find R12 and how many cans do you think it will take to recharge it?

Title: Re: Convert A/C coolant?
Post by: mdsalemi on May 10, 2025, 16:28:53

R12 is available on eBay.

Plenty available at about $50/can.

Better ensure your system doesn't have any leaks first!

Title: Re: Convert A/C coolant?
Post by: Peter on May 11, 2025, 11:02:51

Duracool 12a is a good replacement in Europe, I don't know if it is available in the USA.
Given the low environmental impact of Duracool 12a, the use of this refrigerant for
service applications is not yet limited: this refrigerant will therefore remain available for an
indefinite period of time in order to be able to continue to maintain existing air conditioning systems. Filling an old R12 installation with Duracool 12a can therefore be seen as a sound "long-term solution"

Title: Re: Convert A/C coolant?
Post by: OldGuard60 on May 11, 2025, 11:30:11

Yep.  Any idea on how much R12 I should buy?

Title: Re: Convert A/C coolant?
Post by: Peter on May 11, 2025, 11:44:33

No, i don't know, but the airco specialist might.
I use, after complete overhaul r134a. 800 gram was loaded then.

Title: Re: Convert A/C coolant?
Post by: doitwright on May 15, 2025, 04:48:15

If you are going to take the DIY approach with your A/C, I recommend this book:

Title: Re: Convert A/C coolant?
Post by: OldGuard60 on May 15, 2025, 11:59:59

Thanks for this, but I'm not about to do the DIY route on this car.  Just trying to make sure a mechanic I met is telling the truth.