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ok... so i've decided to do the conversion to 134A cuz i don't think its been done already on my 87 300E. can't go another summer without a/c. i've read how to do it, but now i don't know where the valve is! LOL

i think i've found it but not sure. and yes, i'm gonna do the dye check to check for leaks and all and do the sealant. not sure when it was last recharged cuz i just got the car last summer. the blower works just fine, it just blows warm air.

so can anyone tell me where the valve is located???
 

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Why are you converting to R134a? There is no reason to. These cars don't like R134a and will not cool down to the temp that R12 did. The condensor simply isn't the correct size to offset the lost efficiency of R134a. R134a is also more corrosive and will escape from even smaller holes then R12 will. There will be no need to convert anything and the car will cool correctly if you stick with R12. Just make sure to leak test/pressure test the system and fix ALL leaks, evacuate the system once the leaks have been fixed, then swap out the O rings, install a new drier, then refill with R12 to correct factory specs. Do NOT skip replacing the drier and do NOT skip evacuation. If you do, then your system is going to be toast in no time.
 

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because i don't think that i can do it myself sticking with R12. i'd have to take it into the shop to do this...
 

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because i don't think that i can do it myself sticking with R12. i'd have to take it into the shop to do this...
Do you have a machine to evacuate the system? I'm betting not. Do you even know what a drier is, let alone how to install one without exposing it to the air? I'm going to bet not again. You are going to need to take it to a shop no matter what. If you DIY this, you are going to fry your compressor. Those are not cheap to replace. It's a whole lot cheaper to do it right the first time.

You can't just dump cans of R-134a that you purchased at Wal-Mart into an R-12 system. It seems that is what you want to do.
 

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I agree with Mr. X.

When I bought my 300TE, it had already been converted to R134 by the previous owner at the dealership. I have the service documents for that procedure and it wasn't cheap.

Yes, the cost of R134 is less than R12, but it irritates me that even when fully charged the AC does a poor job of cooling down the car.

If I were you, I would look at the cost and convenience of R134 as a mirage in the desert which will leave you cooking in the sun.

Just my 2 cents.....
 

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There is no way I can get R12 in California. Remember the ozone? All stores are selling 134a only.
 

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There is no way I can get R12 in California. Remember the ozone? All stores are selling 134a only.
Sure you can. Buy it online wholesale with an intent to resell. Resell it to your EPA licenced mechanic for $0.01. 100% legal because your mechanic is doing the install and you resold it. R12 doesn't cost much more then R-134a online. It's actually cheaper to stick with R12 if you do it this way, then it would be to covert to R-134a at your local garage. I've swapped older Mercedes back to R12 because of their crappy cooling performance on R-134a.
 

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If done correctly, the 134A conversion is much more convenient and easy for the non DIY to deal with in the long run. R12 is much more expensive in most locations.

In a location like Seattle, where there are pretty harsh environmental laws, R12 would tend to be a real PITA to work with and 134A is a much more simple solution.

Also, with the Pacific Northwest environment, 134A will cool just fine, even with the humidity.
 

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I replaced the freon on my BMW with Freeze12 I bought on ebay. The seller says Freeze12 is R12 replacement if you can't find R12. It seems to work fine.
 

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If done correctly, the 134A conversion is much more convenient and easy for the non DIY to deal with in the long run. R12 is much more expensive in most locations.

In a location like Seattle, where there are pretty harsh environmental laws, R12 would tend to be a real PITA to work with and 134A is a much more simple solution.

Also, with the Pacific Northwest environment, 134A will cool just fine, even with the humidity.
The EPA governs all states and has set the standards for automotive refrigerant. There are no areas where it is 'harder' to work with. You just need to find a mechanic that will work with it. The newer guys won't touch the stuff because they never worked with it. You just need someone with experince. Will R134a work OK in the North in these classics? Yes, BUT for nearly the same price as a full 134a conversion...you could keep the car on R12. That is a no brainer. If you are in the South or Mid West, then R12 is a must. R12 really isn't that expensive online. Freeze-12 is even cheaper and works just about as well as R12.
 

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Go ahead and do the conversion. If you have lived for some time with no AC, then the ~90% (vs R12) cooling you will get from 134 wiil seem like a godsend. Does your car currently have refrigerant in it? If so, you will have to have it removed and captured by a certified tech as you can't release refrigerant into the atmosphere. If there is no refrigerant left in the system you will want to pull a vacuum on the system to make sure you don't have any major leaks. You can do this yourself with a cheap set of AC gauges and a vacuum pump from Harbor Freight.

If you have small leaks, you might be able to get away with a sealer like Cliplight Super Seal Pro ( this stuff seals leaks in metal components as well as rubber and I am told it is used by MBUSA as an alternative to replacing evaporators). You will also probably want to replace the drier or at least heat the old one while it is under vacuum to remove any water that has accumulated in the dessicant over the years. I have converted several cars over the years, mostly American, but also an Audi and one Merc and I was not able to tell much of a difference between R12 and R134.

Good Luck
 

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i was able to get R12 (albeit not as cheaply) installed in my car a few years ago. last i talked to my mechanic he could still get it/ had it.

it subsequently got in an accident and had R134 installed.
 

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i was able to get R12 (albeit not as cheaply) installed in my car a few years ago. last i talked to my mechanic he could still get it/ had it.

it subsequently got in an accident and had R134 installed.
Did you read anything on the first page? Yes, you can still get R12 (easily). And no, you don't have to get ripped off and buy it from a mechanic.
 

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Freeze 12

Freeze 12 is a mix of R134a and R142 (propane). One should not top off R12 with Freeze 12, i.e., mixing R12 with R134a. People do it anyway because it works short term.
 

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Go ahead and do the conversion. If you have lived for some time with no AC, then the ~90% (vs R12) cooling you will get from 134 wiil seem like a godsend. Does your car currently have refrigerant in it? If so, you will have to have it removed and captured by a certified tech as you can't release refrigerant into the atmosphere. If there is no refrigerant left in the system you will want to pull a vacuum on the system to make sure you don't have any major leaks. You can do this yourself with a cheap set of AC gauges and a vacuum pump from Harbor Freight.

If you have small leaks, you might be able to get away with a sealer like Cliplight Super Seal Pro ( this stuff seals leaks in metal components as well as rubber and I am told it is used by MBUSA as an alternative to replacing evaporators). You will also probably want to replace the drier or at least heat the old one while it is under vacuum to remove any water that has accumulated in the dessicant over the years. I have converted several cars over the years, mostly American, but also an Audi and one Merc and I was not able to tell much of a difference between R12 and R134.

Good Luck
I disagree. I have a 1989 300ce which was converted and it's hell trying to drive here in Cali during the summer. I've had it checked a few times, had the dryer changed, the compressor replaced, and the AC was upgraded due to the fact that r12 isn't available here in Cali. I had no choice at the time. R134 is pure crap when it comes to MBZ's. My friend has a 2005 550clk with 134 and it takes forever to cool. Sitting in traffic is the worst. It is ok, but not cold at all. My 1998 Toyota Tacoma does a better job with 134.
 
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