Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

orifice tube or expansion valve, causing a blockage and loss of cooling. Such blockages also
can prevent the circulation of oil in the system, starving the compressor for lubrication. If the
condenser is dirty, why not just replace it? That’s what many experts recommend. But
condensers are expensive to replace. The alternative is to clean the condenser with an
approved flushing chemical that hopefully will remove most or all of the contaminants. Flushing
can save a customer a lot of money, but it also increases the risk of a repeat compressor failure
or an orifice tube or expansion valve blockage if the flush fails to remove all of the gunk from the
condenser. To reduce the risk of residual debris from a flushed condenser passing into the
system and causing problems, an in-line filter should be installed in the liquid line after the
condenser to trap any debris before it can cause trouble. A filter screen also should be installed
in the suction hose at the compressor inlet to trap any junk before it can enter the compressor.
Debris can be blown backward into the suction hose and evaporator by a compressor failure,
too, so don’t overlook this part of the system if you’re flushing to get rid of contaminants.
960 Condenser Leaks. See the discussion on steel bolt-on-aluminum tube leaks.
Evaporator
Replacement.
740/940 Procedure.
The most difficult
thing about this job
is finding all the
screws that need to
be removed. Plan
for a full day. MCC 740/940 Lower Plenum Cover Beneath Evaporator
Patience is vital,
because if parts of
the evaporator
housing are
damaged, you will
have a very difficult
time remounting the
blower and
obtaining a
satisfactory seal. I
paid $175 from fcpgroton for a new evaporator. The dealer will charge you about $1000-1200 to
replace the evap and recharge the system.
1. Take appropriate safety precautions. Consider disconnecting battery for extra safety.
2. Properly drain refrigerant
3. Disconnect evaporator to drier/receiver connections in engine compartment. Be careful to
use 2 wrenches to apply the proper amount of counter-torque to prevent damage. Be
sure to have new o-rings on hand. Tightly plug the drier open connections immediately