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AC Refill

11K views 16 replies 12 participants last post by  GDC 
#1 · (Edited)
My AC has stopped blowing cold air, and it's time for a refill. Has anyone here tried one of those presureized bottles you can pick up at autozone/walmart? Do they work on a 1988 mercedes 300CE, and is the process easy? Where exactly do you fill it? Will the nozzel just fit onto the hose where you fill it in? Also I have come to understand that there are two different types of stuff that you put in. R12 Freon for older cars and R134A. What year did Mercedes stop using R12 freon? Thanks for the help guys.
 
#4 · (Edited)
R12 is about $60 per pound and works much better than a "converted" system to R134A.
Good Luck,
Jayare

I was in this crossroad years ago when my 92 300E developed a freon leak and had to be fixed. I researched and this is what I found:

1) You can't buy freon 12 directly. You can go to an authorized auto air conditioning service shop to have it recharged. But, they won't re-charge until you fix the leak. This usually leads to system overhaul in which the cost is comparable to putting a new system.

2) In CA it's difficult if not impossible to find a shop who would fix (or touch) an R12 filled system. They usually recommend conversion to R134a. I don't want to give up my R12 so I continue my research and I found that you can buy R12 if you are a qualified HVAC or Auto Air conditioning technician. To be qualified you can take an online exam and pay $30.00 (I think). So for $30 and exam I can buy R12, I'm set...I can do that!

3) No go, because I can't find R12 in small quantity they sell it in bulk like 20-50Lbs. minimum. The cost of R12 , charging lines and pressure gauges plus the cost of parts that may need replacement is almost equal to having a shop fix it. Not counting the trouble of taking an exam.

In the end I gave up R12 and had my system converted to R134a. With parts and labor it cost me $800.00 (IIRC). I didn't notice the difference between R12 and R134a. I was happy with the conversion but I totaled the car (thats another story). Currently, all my vehicles came originally equipped with R134a system and I don't feel it less cooler than R12.

Note: My experience is in So. Cal, USA. If you are Europe, South America or Asia, it's a different ball game or this may not even be an issue.

Good luck!
 
#3 ·
Your car is R-12, unless it has been converted. If you are out of R-12, then you have a leak somewhere in the system. You need to find the leak and repair it BEFORE you re-charge the system. You also need to install a new drier. Once that has been done (and the system has been pressured tested!), then a licensed pro can refill the system with R-12. You can buy R-12 at wholesale prices online and then resell it to your mechanic for $.01. It's perfectly legal to do and MUCH cheaper then buying it from a mechanic who most likely doesn't stock it.

Do not buy a R-134a can from your local auto store and try to refill it!!! R-12 and 134a CANNOT be mixed. And NO, you cannot buy R-12 at the auto parts store.

Don't convert your car to R-134a no matter what anyone tells you. The condenser isn't the correct size and the car was not made to run on the stuff. It won't cool down to the level that R-12 will either. There is about 7-10 degree difference in these cars.
 
#7 ·
R-12 does just vaporize into thin air!!! That is impossible. It's going to somewhere, and that somewhere out into the atmosphere. One of your O rings is most likely fried and has caused a slow leak. That is the most common on older vehicles.
 
#6 ·
My 94 is equipped with R134a I believed. Does this mean I can get the R134a can and recharge myself or better to brint it to the shop?
 
#8 ·
Make sure that it has R-134a. That was one of the first model years to have it.

Then bring it to a shop and have them leak test it with UV die. Repair any leaks, replace drier, then refill.
 
#13 ·
That's also a good idea. Freeze 12 is DIRECTLY interchangeable with R-12, however it doesn't cool down the temp that real R-12 does. It's really close (most wouldn't notice), only off by 2-3 degrees.
 
#10 ·
For sure, R134 is not as efficient as R12. That being said, my 92 300E was converted to 134 and it cools just fine here in the SE US. Maybe it has the bigger condensor and it does have two fans, which help. Also, the blower output is pretty impressive. So, I have no complaints.

I am, however, debating what to do on my son's 190e, because it has a smaller condensor and one fan, and people report that the 134 is a bit weak for the 190. Also, it has a leak and I need to do some work, like some o-rings and a receiver/dryer. If I do that, I might go with r134. I also might try Freeze 12 or maybe just use the R12 that I have, if I can fix the leak.
 
#11 ·
AC

If you have the R134 in your system the fittings will be changed also R-12 is different fittings. If it says R134 you chan buy the recharge cans no sweat. The original poster is R-12 so hes stuck sorry to say. Its ann easy convert to R134 but spendy. The drier gets replaced, then the Orings and fitting then it gets charged.
 
#12 ·
A/C can be a crap shoot. We have cars that are pretty much in the neighborhood of 20 years old. R12 is expensive, but not impossible, however, we have known evaporator issues around 20 years as well as the expected rubber deterioration in the hoses and o-rings. I've done a lot of A/C work and live in the hottest climate, short of living in Saudi Arabia and a simple 134 conversion is about the best way. First see if you have any freon left in the system, just press down quickly and see if anything comes out, not that I condone letting out R12 in to the atmosphere, but a quick pssst to see if anything comes out is ok. If nothing, then you have a leak. The only way to see where the leak is, is to have pressure and dye in the system. So next you must flush the system, most places will do this cheaply or there are over the counter kits available, flush out the old system, and let it dry out. then you can have it recharged either professionally or yourself, either way, I would recommend that you have the system vacuumed, the little bit of air that is left will cause a pressure fluctuation and poor cooling. Recharge it with the proper amount of ester oil and a bit of dye. easter is commonly referred to as "conversion oil" because it is compatible with both R12 and 134, and is less likely to seep out you old rubber. charge with about 10-15% less that the R12 charge capacity, and enjoy it while it lasts, then hunt your leak.

The industry like to scare people in to thinking that most leaks are small, expensive and hard to trace. For the most part you can see leaks as oil seepage around fittings and where the rubber to metal seams are on hoses. if you cant see any dye leaks and it takes about a season to leak out, you have the dreaded evaporator problem. If you have a hose leak, they can be replaced either by getting new ones, or the way I prefer is I have a hose man that will replace the rubber portion of the hose and even repair the metal portion if need be, the can be the most inexpensive way because most low side hoses have a fuel cooler integrated in to them and are sky high!

134 in my 88 300E with the original compressor cools as good as I would expect, yes it does take about 2 minutes @ idle when its 120 degrees outside to get cool, but thats not bad considering thats pretty f-ing hot and my windows aren't tinted. Yes, by the book, you are supposed to change the drier and all the o-rings and the hoses may go bad as well as compressor seals. But find an experienced mechanic, who knows a/c well and they will tell you the same. Use 134 and trace your leaks from there. if you have to replace an o-ring or a hose because it leaks, it will be more expensive to put R12 in your car every time the A/C system has a leak, seeing as everything about is old! But if you do end up making repairs, the drier is cheap and if it helps you sleep better at night, throw one in. however the compressors are pretty tough, and mine has been working well for a while now, even under extreme conditions.
 
#14 ·
The only downside to using freeze12 is that unless you lie about what's in your system, you'll never get any auto shop to hook their equipment up to your car again. Freeze12 doesn't mix with R134A, and even though it mixes with R12, most shops won't wan't to mix it with the recovered R12 that's in their R12 machine (or have it go through their machine at all). You'll be stuck with charging from a can and venting the system to the air to drain it (which is NOT a good idea). I'd stick with R12 or R134A, as good as the alternatives are.
 
#15 · (Edited)
If I haven't missed something here, it looks like R12 is still obtainable in North America but not via retail channels (recovered stuff, presumably, as manufacturing stopped more than 10 years ago?). I believe it is no longer legal to use it in the UK (or the rest of the EC). That's why my A/C man fitted an Airco Retro-Pro conversion kit for about $100; seems fine to me, and he spoke of having fitted dozens with no problems.

http://tinyurl.com/6cl5lf
 
#16 ·
If I haven't missed something here, it looks like R12 is still obtainable in North America but not via retail channels (recovered stuff, presumable as manufacturing stopped more than 10 years ago?). I believe it is no longer legal to use it in the UK (or the rest of the EC). That's why my A/C man fitted an Airco Retro-Pro conversion kit for about $100; seems fine to me, and he spoke of having fitted dozens with no problems.

http://tinyurl.com/6cl5lf
Did you miss my first post? R-12 is AVAILABLE!
 
#17 ·
FWIW

I had an evaporator leak in my '94 E320 going on two years ago. I was losing a full charge of R134 in 3 days. Evaporator replacement is a very expensive proposition, so I did a lot of research and learned about a product called Cliplight Super Seal Premium. My system was empty, so I bought a cheap vacuum pump and set of AC gauges from Harbor freight as well as a can of Super seal. I followed the instructions to on the can to the letter and now my AC works fine and I have not had to add any R134 for almost two years.
 
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