Galant V6-2972cc 3.0L SOHC (1988)
Evaporator Case: All Technical Service Bulletins
A/C - Odors
No.: TSB-88-24-004
DATE: October, 1988
MODEL: All Models
SUBJECT:
MICROBIAL GROWTH ODORS FROM
HEATING AND A/C SYSTEMS;
CLEANING A/C EVAPORATORS
PURPOSE
Customers may experience odors emitted from the heating and air conditioning system, primarily at start-up in hot, humid climates. This odor may be the
result of microbial growth somewhere in the vehicle. This bulletin provides general information on how to diagnose and correct this condition. The
information contained in this bulletin is applicable to automobiles In general, and is not indicative of problems occuring on Mitsubishi Motors vehicles.
DETAILS OF CONDITION
In general, microbial growth (fungus, mold, mildew, etc.) is usually characterized by a complaint of a "musty odor" or "pungent odor" Inside the vehicle.
Odors usually occur when something has been dampened for a period of time, such as carpets or items left in the car, the air intake plenum, the heater/air
distribution assembly, or the A/C evaporator. If the air intake control is set to "Recirc," odors from around the passenger front floor area can get pulled
into the ventilation system of the car, and be misdiagnosed as A/C evaporator microbial growth. The following are suggestions to help pinpoint the
source of the odor. Keep in mind that the sense of smell can vary widely from person to person, and that the odor may occur intermittently.
CARPETS - If the complaint is of a "musty odor" upon merely entering the vehicle, fan and A/C off, check for the possibility of mildewed carpet and
padding, or mildewed upholstery caused by water entry. You will most likely find mildewed carpet and padding that will need to be dried and treated
with a disinfectant or carpet cleaning solution. The source of the water which caused the mildew must be found and corrected as well, some of the
possibilities being a clogged sunroof drain tube or A/C evaporator drain tube, or incorrectly repaired collision damage (poorly sealed windshield,
missing body plugs, etc.).
AIR INTAKE PLENUM - Odors do not usually come from the plenum, except when debris has collected, clogging the drain channels. The mold and
fungus usually grows on the debris, not the vehicle, whenever there has been moisture present. Rainy weather, car washing, dew and fog can all supply
moisture to the debris in the plenum and trigger microbial growth. Seldom will you find the plenum to be the source of the odor in hot, dry environments.
If the odor never occurs during damp conditions with the air intake control set for Outside Air, you have eliminated the plenum as the source of odor. If
the plenum is the source of odor, you will need to remove the cowl trim and clean out the debris that you will probably find there. This area should then
be flushed with water to assure that the drain channels are clear.
HEATER/AIR DISTRIBUTION ASSEMBLY - This area is seldom a source of microbial growth odor, as there are few or no low spots in our heater/air
distribution assemblies that will collect moisture for any length of time. The odors associated with this area are usually that of a heater core leak, of
which antifreeze has its own distinct odor.
A/C EVAPORATOR - If the complaint is that the odor occurs whenever the fan is turned on after being off for a while, or that the odor occurs whenever
the A/C is turned on or off, the evaporator is the likely source. The odor will also occur as described regardless of the air intake setting. If the A/C
evaporator is diagnosed as being the source of odor, there are two methods of cleaning it. One method is to remove the evaporator assembly and wash it
in a disinfectant solution. Another method is to gain access to the evaporator core while it is still in the vehicle and spray the evaporator core with a
strong disinfectant solution. Which method is used will be determined by the extent of the cleaning necessary, and whether it is easier to remove the
evaporator case or blower assembly. These two methods are described In more detail.
EVAPORATOR CLEANING
NOTE:
Read all instructions before performing procedures.
REMOVING AND WASHING THE EVAPORATOR ASSEMBLY
PROCEDURE
1.
The A/C system should be discharged and the evaporator assembly removed from the vehicle as described in the appropriate Service Manual.
2.
Disassemble the evaporator assembly and wash only the plastic housing, foam inserts, and the evaporator core in a disinfectant solution such as or
similar to Lysol(R). The open freon tubes should be capped tightly before washing the evaporator. Rinse in fresh water.
3.
Dry all parts immediately and thoroughly. Before reinstalling the evaporator assembly into the vehicle, make sure the condensate drain tube is
clean and free from obstructions.
4.
Recharge the A/C system with freon and check for air and freon leaks, and that the evaporator is draining properly.
