Opel Frontera UBS. Manual - part 907
1B – 22 AIR CONDITIONING
Almost transparent.
A flow of bubbles
can be seen, but
they disappear
when the throttle is
opened.
The sight glass provides accurate diagnosis only under the following conditions.
If the vehicle can be tested under these conditions, check the sight glass appearance and compare to the
chart.
*
Engine speed Idling
*
A/C switch “ON”
*
Blower fan operating at highest speed
*
Air source selector lever at “RECIRC”
*
Temperature control knob at coldest position
*
Ambient temperature below 30°C (86°F) and humidity below 70% (See NOTE 1)
*
High side pressure less than 1863 kPa (19 kg·cm
2
/ 270 PSI) (See NOTE 2)
NOTE 1
If the vehicle cannot be moved to a testing location that meets these specifications, then the sight glass
cannot be used for diagnosis. You must discharge and recover the refrigerant, then recharge the system
with the specified amount of refrigerant. Then continue checking the system performance.
NOTE 2
If the high side pressure is greater than stated, the sight glass cannot be used for diagnosis. You must
discharge and recover the refrigerant, then recharge the system with the specified amount of refrigerant.
Then continue checking system performance.
Reading Sight Glass
High and low
pressure pipe
temperature
Sight glass
condition
Air condi-
tioner cycle
condition
The high pressure
pipe is hot and the
low pressure pipe is
cold. There is a dis-
tinct difference in
temperature bet-
ween them.
OK
The high pressure
pipe is warm and
the low pressure
pipe is cool. There
is no great dif-
ference in tempera-
ture between them.
A flow of bubbles
always can be seen.
It appears some-
times transparent,
and sometimes
frothy.
NG
(Not enough
refrigerant)
There is little dif-
ference in tempera-
ture between the
high pressure pipe
and the low press-
ure pipe.
Something like fog
faintly can be seen.
NG
(Almost no
refrigerant)
The high pressure
pipe is hot and the
low pressure pipe is
slightly warm.
There is a difference
in temperature bet-
ween them.
Even at idle with the
fan at “HI” (with the
window fully open),
the bubbles cannot
be seen.
NG
(Too much
refrigerant)