Hey Gary,
One thing you may want to check: The evaporator is housed in a cast aluminum
case. At the bottom of the metal evaporator case are 4 openings nearly 2 inches
in diameter. These openings, presumably for additional drainage of the
evaporator, are regulated by little rubber-like discs on a stem. Since the
blower on this car pulls air over the evaporator, it creates negative pressure
in the evaporator housing. The theory, I suppose, was that these little rubber
flaps would close when the blower was on, thereby sealing the evaporator
housing to prevent intrusion of air from the engine compartment throught the
cowl drain openings in the firewall (and who knows where else?). The problem is
that these little rubber flappers become hardened, disfigured or just plain
broken. When this occurs, your blower is sucking nice warm air from the engine
compartment and trying to cool it. My a/c guy found this situation when he
removed my evaporator trying to find a warm air leak. Since there is already a
drain tube in the evaporator case, he saw no re
al need for the additional drain holes, sealed them up with a piece of metal
and put the whole thing back together. Of course, you have to remove your
evaporator to get to these little devils. But the trouble was worth it. My
AirTemp (with 134a) went from 50 to 40 degrees at the vents on hi fan. At med
and lo blower speeds and on an open stretch, it has dropped down to 32. Not
bad, by any standard.
So far, so good.
Mark Harris
'65 Crown Four-Door
'67 Mobile Director
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