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Old 05-11-2003, 10:58 PM
tivoliman's Avatar
Happy with Mercedes
Join Date: Dec 2002
Location: New Jersey
Posts: 360
Air Conditioning - Conversion to "New Freon"

Please comment on the conversion to "the new freon".

Car: 190E 2.6; 1992
Air conditioning seems to work, but not real cold - sort of cool. My guess is that it needs some feon added.

But I guess "The right thing t do is to install a conversion compressor."

What are your thoughts?

Are there "Kits with all that is needed" to conver from old freon style to new freon style?
Thanks for the help
Bill Fisher

'86 560SL (186K) - Now a 'classic' : Registered as an Historic Vehicle
'95 E420 (188K)
'03 LS430 (Lexus)
- - - - -
'95 E420 (231K) Sold to a happy buyer, new to Mercedes
'90 300E (65K) Sold to an Mercedes Lover
'92 190E (215K) - retired to the salvage yard, sigh
'93 500SEL (214K) - Moved to another family, still runs like a young pup
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Old 05-12-2003, 07:18 AM
Posts: n/a
If the system has never had refrigerant added, it could be that it just needs topping up. It is not uncommon for a system to lose an ounce or so a year. In 13 years this means about half the refrigerant is gone.

Even if there is a leak, you will be far better off and save money by repairing the leak and recharging with R12.

It is very common for people at the slightest hint of an a/c problem to want to change it to 134 (the "new" freon.) This is in most cases false economy. To convert the system correctly, it should be thoroughly flushed, change filter drier, drain compressor and flush with Ester, add Ester and, of course, repair whatever problem there was that caused the problem in the first place. If you stay with R12, on the other hand, you simply repair the problem that you must repair any way and charge with R12. This is in almost all cases the least expensive way to go PLUS you will retain the cooling capacity of the R12.

When changing to 134 you lose about 15 to 20% of the cooling capacity.

What you should do is look for a leak. If there is a leak, fix it and recharge. If there is no leak, then top it up with R12.

Good luck,
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Old 05-12-2003, 11:39 AM
csnow's Avatar
Registered User
Join Date: May 2002
Location: Mass
Posts: 1,127
Like Larry said.

Just do not fall for a blend. With names like Freeze 12, FR-12, or whatever. Another poster was recently 'misled' into a blend conversion.

Insist upon r-12(Dichlorodifluoromethane), and make sure they understand.
Also, try to avoid paying for a full evacuation and recharge. R-12 topoffs really are legal, and any shop that says otherwise is misleading you. If it took many years for cooling to degrade to this point, you probably do not have a repairable leak.
1986 300E 5-Speed 240k mi.
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Old 05-12-2003, 02:44 PM
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Join Date: Mar 2003
Location: New Hampshire
Posts: 158
I am the other poster

I just got my AC recharged, and after thinking I was getting R-12, i found out the shop put in "Freeze 12". Now I have a contaminated system. We havent had a really hot day yet for me to try it so I dont know how well it works. Any way just make sure they will only use the R-12, no substitutes, before any work is done on the car.
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Old 05-13-2003, 12:58 AM
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Join Date: Apr 2002
Posts: 321
what is the cost of r12 these days?

and the cost of the new stuff?

i think it may be a considerable differential.

so, if you have an older benz that develops a/c problems that result in a continuing loss of r12, it might pay to revise the system to use the new stuff.

i have made that conversion for my 1986 560sel[250,000miles] and my 1987 560sec[80,000miles].

i can detect no deterioration in cooling capability. and the cars operate in the environs of the texas gulf coast, a tough test.

just some thoughts.
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Old 05-13-2003, 07:29 AM
Posts: n/a

You do not say where you are located. If you are in Texas or in another hot, humid area I expect you would notice the difference.

R12 goes for as little as $20 per pound now.

Converting a system to 134 in almost all cases is false economy. To convert properly, you must remove, empty and flush the compressor, flush all components, put in Ester oil, use 134 compatible o-rings everywhere, change pressure switches and expansion valve, evacuate and charge.

You should not convert a system unless there is a problem. If there is a problem it typically will cost much more than the refrigerant that goes back in.

In most cases you will not know the difference in refrigerant cost and by staying with R12 your system will in most cases last longer and in all cases cool better.

Have a great day,
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