Chevrolet 70 Series 1970, Service Manual

Page: 161 / 841

CAB AND BODY MOUNTINGS 1-130
Figure 25—Compressor Fitting Installation ITypical)
E xplore for le a k s by moving end of sam pling
tube around a ll connections and points w here a
leak may b e. Check around bottom of connections,
sin c e R e frig era n t-12 is heavier than a ir and w ill,
th erefo re, be m ore apparent at bottom of fitting.
CAUTION: DO NOT breathe the fumes
and black smoke that are produced if the
leak is a big one. They are poisonous.
Any time an open flame is used near a
vehicle there is a certain amount of dan­
ger. Although the torch flame is small
and well protected, it is recommended
that fire extinguisher be close at hand for
any emergency that might arise.
The color of the flam e w ill turn to a y ello w -
green when a sm a ll leak is detected. L arge leak s
w ill be indicated by a change in color to b rillian t
blue or purple. When the suction h o se i s moved
away fro m the lea k the flam e w ill c le a r to an a l­
m ost c o lo r le s s p ale blue again.
LIQUID-TYPE LEAK DETECTORS
T h ere a r e a number of fittin g s and p la c e s
throughout the a ir conditioning unit w here a liquid
leak d etector solution may be u sed to pinpoint le a k s.
By m erely applying solution to the a rea with
the swab that is u sually attached to the bottle cap,
bubbles w ill form within secon d s if th ere i s a leak .
For confined a r e a s , such a s se c tio n s of the
evaporator and condenser, the torch -typ e d etector
i s the only p ra ctica l kind which should be u sed for
determ ining le a k s.
ELECTRONIC LEAK DETECTOR
An electro n ic lea k detector for detecting r e ­
frigeran t lea k s i s a lso availab le. In stru ction s for
operation of th is type d etector a re supplied with
the unit.
REPLACING COMPRESSOR
The c o m p resso r rem oved m ust be c lo se d im ­
m ed iately. See low er V iew of figu re 25 which show s
a c lo su r e plate which can be im p ro v ised and in­
sta lle d a s shown.
If the sy ste m has been o r can be operated for
m ore than two m inutes, circu lation of o il fro m the
c o m p resso r to other com ponents of the sy ste m w ill
require adjustm ent of the o il charge in the new
c o m p resso r a s exp lain ed p reviou sly, under "Adding
O il To C om p ressor."
A fter draining and m easuring the o il fro m the
cra n k ca se, the amount that has m igrated to other
p a rts of the sy ste m can be determ ined by subtract­
ing the amount drained from the orig in a l o il charge
of 11 fluid o u n ces. The amount of o il equal to th is
lo s s sh a ll be drained from the new co m p resso r
a ssem b ly b efore it is in sta lled .
COMPRESSOR SEAL
The e x isten c e of sligh t am ounts of o il in the
im m ediate a rea surrounding the co m p r e sso r is
NOT n e c e ssa r ily an indication of a leaking s e a l.
It m ust be rem em bered that a ll m oving p a rts need
lubrication. F or th is rea so n , the c o m p resso r is so
designed to allow a slig h t flow of o il into the a rea s
of the co m p r e sso r beyond the s e a ls . Since the com ­
p r e s s o r com ponents a re rotated at high sp eed s,
so m e of th is o il may be thrown off the rotating
p a r ts. Consequently, do not rep la ce co m p resso r
s e a l until the sy ste m is p rop erly ch eck ed for le a k s.
CHEVROLET SERIES 70 90 HEAVY DUTY TRUCK SHOP MANUAL