Hummer H1 Service Manual page 726

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Checking/Adding Refrigerant Oil
It is not necessary to check or add oil as routine maintenance. It
is necessary to add oil when the evaporator, condenser, com-
pressor, or receiver/dryer has been replaced, or there was a
large leak. When a system is discharged, it is also necessary to
replace any oil carried out with the refrigerant.
CAUTION: All replacement compressors are shipped with 8
oz. (237 ml) of oil in the crankcase. This oil must be drained
completely, and replaced in like amount to the failed compres-
sor. Add 2 oz above what is found in the failed compressor.
Failure to do so will cause an overcharge of oil in the system
and will lower cooling efficiency. An extreme overcharge con-
dition may cause early compressor failure.
1. If a major component was replaced, add clean GM PAG
oil as follows.
a. Condenser – 1 oz. (30 ml).
b. Evaporator – 3 oz. (84 ml).
c. Receiver/Dryer – 2 oz. (60 ml).
d. Auxiliary Unit - 2 oz. (60 ml).
e. Compressor – see step 3.
f. Any other known quantity of oil.
2. Add oil to the system. Add directly into component. Oil
can also be added directly from the service cart after
system evacuation.
3. Check oil in compressor:
a. Recover/discharge A/C system refrigerant.
b. Remove compressor.
c. Tip compressor on hose connection end and drain into
a clean container. Allow to drain for ten minutes.
Measure and discard oil.
d. When the new compressor is recieved, drain the oil
that was shipped inside. Replace the oil in an equal
amout to that which was drained from the old
compressor. If less than one ounce (30 ml) is drained
from the old compressor, add two ounces (60 ml) to
the new compressor. If more than one ounce (30 ml)
is drained, replace the same amount in the new one.
e. Plug or block ports and turn compressor over slowly
several times.
05745159
Heating/Ventilation/Air Conditioning (HVAC)
4.
Charging The A/C System
NOTE: If A/C system requires replacement of a major compo-
nent, refrigerant oil must be added to system to compensate for
loss.
1.
2.
3.
4.
WARNING: Make sure high-pressure gauge valve is in
closed position on manifold gauge set during charging.
Failure to do so will cause compressor to build pressure in
refrigerant container. This could result in injury to per-
sonnel or damage to equipment if the container cracks.
5.
6.
NOTE: Keep refrigerant container upright at all times so re-
frigerant enters system as a gas.
7.
8.
Perform evacuation, recharging, and leak testing of
system.
Evacuate A/C system. Follow manufacturer's recom-
mended service procedures for the equipment being used.
Connect refrigerant source to center hose if manifold
gauge set J–39183-C is being used.
Open refrigerant R-134a source to allow refrigerant to
flow into system.
Purge center hose, low-pressure hose, and high-pressure
hose as follows:
a. Slightly loosen center hose at manifold gauge set
center port until refrigerant escapes, then tighten hose.
b. Open high-pressure and low-pressure gauge valves to
allow refrigerant to flow into high-pressure and low-
pressure hoses.
c. Turn high-pressure and low-pressure gauge valves
clockwise to OFF position.
d. Purge high-pressure and low-pressure hoses at service
ports of compressor.
Start engine and set engine speed at 1500 rpm.
Turn A/C system to max cold and blower fan on high
speed.
Open low-pressure gauge valve until system is fully
charged.
Close low-pressure gauge valve.
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