I noticed my A/C had a small leak about 4 years ago. So every 1 to 2 years I have to bring to A/C service center for a re-charge. Since R12 is very expensive, every time I have to pay about $100 for the service, even though they only added about 16 oz of the freon. Some places would not even re-charge for you, because it is against law to fill R-12 in a known leaked A/C system. So I decided to say good-bye to R12, bought R134a retrofit & charging kit for $39.95 from Pep Boys yesterday. I just followed the instructions from the kit, and in 30 minutes my A/C system is running very cool with R134a. Since I know there is a small leak exist in my A/C system, all I have to do is every year or so add 1 can R134a ($6) and some oil charge (o-ring conditioner). I did not replace dryer/receiver or o-rings. One more thing, before being able to charge the vehicle the R-12 needs to be removed. In the old days you could just depress the valve to let what is left of the R-12 out. It is like letting the air out of a tire. But that is against the law. You are supposed to have the R-12 vacuumed out (recovered). I would not tell you how I did mine. The choice is yours. David ______________________ 1985 300D Turbo

Did you evacuate and flush the compressor of the r12 oil ? If so , how did you determine how much oil to put back into the system ? If you did not replace the the Reciever/Dryer are you not worried about adverse effects of mixing the oils there? Greg

Greg, I just converted to 134A also in my 300SD. As I understand it, there are no immicsibility oil problems with the conversion if POE oil is used. Now PAG is another story and I would never convert a R12 car to 134A with the use of PAG. The conversion kits from Pep Boys use a can of POE with refrigerant for the conversion. I too would recommend a deep vacuum for some time to eliminate moisture and all R12 but my buddy has converted over 60 cars so far with nary an inch of Mercury vacuum on any of them! The POE will become the dominate lubricant and the old mineral oil will just sit in all the low spots like reciever dryer, condenser and so forth. Kinda funny: The R12/134A thread is getting to be just like the ole Synthetic vs. dino oil thread......

__________________
Orland Park, IL
1985 300SD 215,000 miles

I did not evacuate and flush the compressor of the r12 oil. The instructions from the conversion kit did not call for that.
My friend converted his 300SD from R12 to R134a last year. He did not evacuate and flush the system, nor did he replaced any o-rings and the dryer/receiver. His A/C system still running good.

When you go to a shop asking for R12 to R134a conversion, they definitely tell you that: you need to evacuate and flush the whole system, you need to replace the o-rings, you need to replace the dryer/receiver. Otherwise they cannot justify to charge you a lot of $$$ for just put in one service pot , 3 cans of R134a and 1 can of POE oil.


David


_____________________
1985 300D Turbo

I did something similar on my old IH Scout. Worked like a charm! Unfortunately, the compressor was on it's way out anyways (bearings were out; sounded like a dying water pump), but for the year or so that I had it, it worked quite well. FWIW, I had a shop evacuate the system completely first, but I don't think they went so far as to flush it. And the R134a was quite cool; worked very well for this area and going up and down California on the I-5.

Just my $.02...I probably used the same kit, BTW.

__________________
2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

Hello everybody:
I am new on this forum. I drive a MB 1985 300D Turbo, 123.
Mileage: 179,000.

I did mine using a similar kit purchased from K-mart for about 29.99( Interdynamics). It works well but I have to add a can or two every year. But Its still cheaper.
My advice, If you dont have a leak its good Idea to have a deep vacuum done to remove all old R-12 and air/moisture traces etc.
Then recharge with new R-134a kit. This I am told improves the life and eficiency.

__________________
One penny saved is three penny earned.

1985 300D Turbo 179,000miles

Yes, you can indeed in most cases have cold air quick and easy with one of these kits. There is an old adage that comes to mind though, that is: "If it looks too good to be true, it probably is."

Evacuating the system is NOT merely a means for the shop to charge you more money. It IS a means of removing the dreaded moisture from the system. The moisture H2O(part hydrogen) mixes with chloride in the refrigerant to make an acid. This acid will eventually eat a hole from the inside out somewhere in your system. For a long term fix, you really need to evacuate the system prior to charging.

This also reminds me of a slogan of the old Fram oil filter commercial, that is: "pay me now, or pay me later."

Best of luck,

Over at aircondition.com they call those $29.99 packages "Death Kits." While thay may be a bit of hyperbole, it is definately better to flush out the mineral oil and vacuum the system. Excess oil lowers the performance of the system, air in the system stresses the compressor, and as Larry has pointed out, water is a long term death knell. The reason the shops are more expensive is because they are doing it right - they don't want you back in a year complaining.

Thank you Larry, I second that.

BOUGHT THE SAME TYPE OF KIT FOR 18.99, 1/2 OFF SALE AT MEIJERS. WAITING TILL THE FAN GETS FIXED FOR THE RECHARGE.

THERE IS A GREY COATING ON THE ENTRY TUBE SIDE OF MY FINS IT ALSO IS ON THE TUBE CONNECTIONS NEAR THE CONDERSER. WHAT IS THIS???

THE COMPRESSOR WAS UNPLUGGED WHEN PURCHASED. I HAVE PLUGGED IT IN BUT AM NOT SURE IF WORKING. I HAVENT SEEN IT ENGAGE. IS THERE A WAY TO "MANUALLY TURN IT ON AND OFF"??

THEY SAY A CHANCE OF SNOW THIS WEEKEND (5-18) BUT THE A/C SEASON IS COMING SOON.

You would not want to direct wire it without being sure your utilizing the high side switch and the low side switch in the circuit.... otherwise you would soon ruin it... and just might explode it like a bomb.

i would not like to see it go off like a bomb. so maybe i'll let a sleeping dog lye.

other posts have stated the compressor will run when defrost is on. so maybe i'll try and test it that way.

still like toknow what the greycoating is on the fins and pipe

As a professional mechanic the thing I would have to say is these kits should not be sold to the public for many different reasons. 1) I as a mechanic am not allowed to dump R12 into the atmosphere, there is a large expense involved with recovery equipment and EPA compliance 2) most do-it-yourself people will do this job on their own and not flush the a/c system and not put a vacuum on it before charging it and then bring it into a shop 6 months later when it doesn't work and complain because the bill to correct their errors is so high

GUYS, THIS IS THE WAY IT WORKS!! My shop rate is $40/hr, if you want to help then it goes to $60, if you played with it first, the rate will be unbearable because I now have to figure out what was done and how to correct it!

There are some things that tooling and experience are required for. Air conditioning is one of them so the job is done correctly.

I totally agree. My friend has a TV repair shop and I see first hand what happens when somone tries to "fix" something then comes to him for help. He has the same pricing structure

300 D Grey, You may have to shoot a digital pic of that grey coating... for us to be able to guess/ascertain what it is... Greg