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Discussion Starter #1
Hi There:

I was pondering this issue over the weekend when I thought about diving into the HVAC system and A/C. My compressor turns freely, but I did not have the car running long enough to try out the air conditioning. How do you know whether your 380SL has the original R12 freon versus the updated R134? I assume I will have to either completely replace or at least top off the freon once I get the heater controls functioning properly, but I don't want to create a problem by putting in the wrong freon.

Is there an easy way to tell if there are no stickers under the hood to confirm if it has been converted to R134. Can I even get R12 freon anymore??

Thanks and any information would be great.

Ted
 

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you need a freon identifier to tell for sure. i have seen customers buy 134a and a conversion fitting install 134a then remove the fitting and put the original cap on. if it has been converted correctly it will have a sticker and new fittings on both high and low side. 134a does not work as well as r12 in the older mercedes keep the system r12 or convert back to r12. i have also seen cars come in with mixed freon or even propane instead of freon.
 

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Plus, there are other 'drop-in' solutions that are not compatible with ether of these.

If you are thinking about retrofitting to R134a - don't. System won't be the same and will have all kinds of slow leaks unless you replace every line seal with a new standard.

Also, compressor has to be compatible. Not every R12-compliant compressor would work with a different refrigerant.
 

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My 73 did not appear to be converter. I got the car and garage hot on a 100 degree day and vacuumed out the system and charged it up with r12. It seemed to cool as long as I owned the car (which wasn't very long).

You can rent or buy a real vacuum for evacuating cooling systems. You need to do this to draw all the moisture out of the system. The hotter and the more vacuum you draw, the more likely you are to get out all the moisture. Then, while still under vacuum, you connect the first can of refrigerant and watch your gauges.

Some equipment I needed:
- r12 manifold gauges (about $35-40, and I can lend these out).
- cans of r12
- r12 can tapper and hose to connect cans to the gauges.
- pot of warm water to keep the cans warm to expel all refrigerant.

This thread may not be very concise, but it was my experience:
http://www.benzworld.org/forums/r-c107-sl-slc-class/1622428-anyone-want-teach-me-ac-part.html
 

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While I suggest against doing this on your own, if you do, you also want to use new dryer and new compressor oil. Don't overfill, as it will toast it.
 

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Discussion Starter #8
I think I have confirmed I still have R12 in my car.

Now the question is, who can I take it to near me to troubleshoot the system and get it working? I live in Downers Grove and anyone who is familiar with my town knows we have just about every car dealership available and several shops who claim to be experts on foreign cars.

I started my search with the local shops who service radiators and cooling systems and since my system still retains the R12 freon, none of them want to touch it. Can anyone recommend a shop near me to work on the AC as well as a few electrical issues?

I would really appreciate a personal referral in lieu of just playing einey, meanie, minie, moe.

Thanks!!

Ted
 

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I think I have confirmed I still have R12 in my car.

Now the question is, who can I take it to near me to troubleshoot the system and get it working? I live in Downers Grove and anyone who is familiar with my town knows we have just about every car dealership available and several shops who claim to be experts on foreign cars.

I started my search with the local shops who service radiators and cooling systems and since my system still retains the R12 freon, none of them want to touch it. Can anyone recommend a shop near me to work on the AC as well as a few electrical issues?

I would really appreciate a personal referral in lieu of just playing einey, meanie, minie, moe.

Thanks!!

Ted
Your best bet is to do it yourself if the shops that are around you dont have anyone who can deal with r12( the best freon for auto use) Its only been twenty years since mb stopped using it find an old retired tech and see if they will do it at home. If you change the parts and they refill with r12 you should be able to find someone that can help. R12 is still being made in mexico so the product is not hard to get and not that expensive anymore.
 

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Easy to tell the difference between R12 and R134 in a 107. If it has somewhat cool duct temperature its R12. If it has lukewarm duct temp its R134.
 
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