1992 190E 2.6 135,000 miles, A/C 7is blowing cool, not cold. Still
running on R12, I am now considering Converting to R134a instead of
recharging with $$ R12 A/C was working perfectly in March, so I
assume no major problems. What are my steps in a conversion? Is
this a DIY? I am told, first to have the system "flushed and
vacuumed'? , how and by who? There must be a small leak. Would
someone please explain the right procedure..............Rick
There are other refrigerants that will cool as effectively as R12 and
are environmentally compliant. I would not fool with R12 in this day
and age-the price only has come down because the demand peak is over.
If you are keeping the vehicle I would do it right.
You can DIY if you are determined, you will need a vacuum pump and a
manifold gauge set as a bare minimum. I would flush the system
thoroughly and depending on which compressor your car has possibly
replace it or open and flush it. Some compressors are user
openable-I've done all sort of things with recip Tech and York
units-although today if you had one of those old battle-axes I'd look
into a Sanden conversion.
Well thanks,... I think. I had heard
that R134a was not cooling as well, but thought it was because it
requires higher pressures . As I recall its been over 3 years since
my system was recharged at 120.oo a pound, I think. Dye was put in,
but I never went back since everything worked. I think this sounds like
leaky O rings ......do you agree? Should I have the system "flushed
and pressure tested" before refilling..... or just topped off.
By the way flushed with what?
Whenever you change from R12 to R134a the only thing that really needs to be
changed is the drier canister. Everything else will be fine, including the
compressor. When you draw down the system you'll remove nearly everything
from the R12 system including most of the oil so you will want to put in at
least one can with an oil charge. If you do decide to switch over to R134a
put in a can with a sealer included in the mixture. I've use this and it
seems to seal any small leak I've encountered. Incidentally, I've change two
of my own MBs to R134a with good results......cold and all that in warm,
sunny S. Cal.
However, having said all of this I'd do as the other fellows suggested and
stay with the R12 as long as possible. It works and, in my humble opinion,
has been thrashed by tree-huggers hoping to make a buck or two on companies
producing R134a since they obviously lost out on the R12 bubble.
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