Re: [DML] Vacuum leak solved...

["David Teitelbaum" <jtrealty@xxxx>]

If the evaporator coil ices up (this goes for a Lincoln too) this
means either you have an undercharge of refrigerent or a valve in the
system is malfunctioning, in either case the suction pressure is
getting too low and the coil freezes the condensate. Another
possability although rare in a car is not enough airflow over the
evaporator coil. This is more likely in a house where the air filter
is really dirty and cutting down the veolcity and volume of air. Since
the coil can't absorb enough heat to keep it from freezing it ices
over. Typically you check for a 20 degree temperature drop over the
coil so if the air entering the coil is 90 degrees you should be able
to measure the air comming out the vent at 70. One of the
disadvantages of converting an R-12 system to 134 is the higher head
pressures and the undersized condensor coil. This translates into
about a 20 % drop in cooling capacity. This subject has been gone over
in the past so you should look in the archives. Some people claim
great success in converting. All of the manufacturers and venders say
bad things can happen, I personally have not seen it yet although it
could still be too soon to tell. There are "drop-in" replacements
available now for a lot less than R-12, you might want to consider
them before trying R-134. Even R-12 shouldn't scare you, even though
it is $60 a pound you only need less than 3 LBS. Just fix all the leaks!
David Teitelbaum
vin 10757



--- In dmcnews@xxxxxxxxxxxxxxx, "content22207" <brobertson@xxxx> wrote:
> Hopefully moderator will let this post through (answers specific
> question):
> 
> Car had been sitting in the sun all afternoon -- was probably well
> above 100 in there. Didn't leave the driveway because car blocked in
> and electric fans start refrigeration cycle OK by themselves (engine
> fans on my Lincolns can't do it sitting still). Checked temp on
> previous charge about 2 weeks ago -- 42.9 degrees. Not as cold as the
> Lincolns, but it is a different system. Will drive DeLo to work
> Wednesday and recheck.
> 
> Interesting note -- last summer bypassed leaking heater core on my Two
> Tone Lincoln. A/C evaporator started icing up like old freezer coils
> (don't tell me R134 doesn't get cold!). Would stop air flow completely
> within 10-15 minutes. Spent whole trip to/from DC alternating between
> A/C and outside vent (to defrost evaporator). Also ended up with glove
> box full of water. Guess Lincolns need residual heat from heater core
> (don't have an accumulator and orifice tube -- use something called
> "throttle suctioning valve". Has to do with Automatic Temperature
> Control). Is same charge felt by people who went to Dave Swingle's
> South Carolina Door Seminar in March BTW, so obviously new heater core
> did the trick.
> 
> 'Nuff said Re: A/C.
> 
> Bill Robertson
> #5939
> 
> >--- In dmcnews@xxxxxxxxxxxxxxx, "Scott Gardner" <gardners14@xxxx>
wrote:
> > Is 52 degrees the temperature at the vents with the A/C on? I've only
> > worked on the A/C systems on a few cars, but that seems pretty high.
> > What's the ambient temperature where you are?
> > 
> > Scott Gardner
> > 
> > -----Original Message-----
> > From: content22207 [mailto:brobertson@xxxx] 
> > Sent: Sunday, May 25, 2003 10:39 PM
> > To: dmcnews@xxxxxxxxxxxxxxx
> > Subject: [DML] Vacuum leak solved...
> > 
> > Related note: removed A/C compressor altogether for driver's side
> > valve cover. Replaced O rings this time (58 cents at the hardware
> > store -- what WAS I thinking). Vacuumed system and recharged this
> > afternoon. Holding steady @ 35 PSI (low side) and 52 degrees.
> > Hopefully will drop as passenger compartment cools down. Since we're
> > entering A/C season, my R134 methods are written up on DMCNEWS website
> > for like minded. Generate a lot of controversy among R12 purists, but
> > the way I figure: if your system isn't putting out now, what do you
> > have to lose? Only change is freon itself (all factory components
> > re-used). If you don't like R134 performance, bleed it back out and go
> > back to R12. Difference is about $120 (to R134's benefit)...
> > 
> > Bill Robertson
> > #5939