A/C ODOR ON TRUCKS (CLEANING PROCEDURE)
MODELS: ALL 1985-89 LIGHT AND MEDIUM TRUCKS WITH AIR CONDITIONING
Some customers may experience odors emitted from the air conditioning system of 1985-89 Light and Medium trucks primarily at start up in hot, humid climates. This odor may be the result of debris in the heater/evaporator case or microbial growth on the evaporator core. To address this condition, the following equipment and procedure should be used:
Required Equipment:
GM Goodwrench Air Conditioning System Disinfectant kit, P/N 25533404
Kent-Moore tool number J-36645 or equivalent Air Conditioning Cleaning Gun
Rubber gloves
SAFETY GOGGLES OR FACE SHIELD (ORDINARY SAFETY GLASSES ARE NOT SUFFICIENT)
NIOSH approved respirator with charcoal cartridges
Pedestal fan
CAUTION:
Procedure should only be performed on a cold vehicle to prevent the disinfectant from coming in contact with hot engine components.
Disinfectant can cause substantial but temporary eye injury. Do not get in eyes or on clothing. Wash thoroughly with soap and water after handling.
FIRST AID: If disinfectant gets into eyes, hold eyelids open and flush with a steady, gentle stream of water for fifteen minutes. Obtain medical attention if irritation persists. Procedure:
1. Put on rubber gloves, and safety goggles. If working on a C/K or Medium Truck which requires being inside the vehicle, also put on a respirator.
2. Pour the small bottle of the two-part GM Goodwrench Air Conditioning System Disinfectant Kit, P/N 25533404, into the large bottle. Seal and invert the large container once or twice to mix contents.
3. Check underneath vehicle to verify that drain outlet is not plugged.
4. Connect battery charger to avoid draining the battery during cleaning procedure.
5. Remove blower resistor as described in service manual, leaving wiring connectors attached.
NOTICE: Do not allow the metal coils of the blower resistor to become grounded to any metal surface as this may result in internal circuitry damage.
CAUTION:
Blower resistor may be hot.
6. Check heater/evaporator case for debris. Remove any debris present through blower resistor opening. If debris is imbedded into the evaporator core face and cannot be removed, the core will have to be removed from the vehicle and cleaned. If a large amount of debris is present in the heater/evaporator case the air inlet screen will require sealing around the air intake in the cowl area.
7. Turn the ignition to the "ON" position but do not start vehicle.
8. Set mode selector to vent, blower switch to low speed and temperature lever to full cold.
9. Open all windows and doors. Exit vehicle.
10. Place drain pan with at least a two quart capacity below heater/evaporator drain hole to collect disinfectant and rinse water runoff. If necessary install additional hose on to drain so that all fluid goes into the drain pan.
11. Turn pedestal fan on high to provide cross ventilation during cleaning procedure.
12. Use Kent-Moore tool J-36645, or equivalent spray gun, capable of delivering two ounces/minute of liquid when driven with 80-90 psi of compressed air. Insert the nozzle of the spray gun through the blower resistor opening and insert siphon hose into container of disinfectant. Direct spray toward evaporator face taking extra care to ensure adequate coverage of the corner and edges, completely saturating the entire core. Use the entire container of solution.
CAUTION:
Do not allow disinfectant to come into contact with hot engine components such as the exhaust manifold.
13. Reach into vehicle and turn the ignition to the "OFF" position, and allow the core to soak for five minutes.
14. Double check underneath vehicle to verify proper drain operation. If necessary, unclog and increase drain plug slits with a razor blade or sharp knife.
15. Reach into the vehicle and turn the ignition to the "ON" position, but do not start vehicle.
16. Thoroughly rinse the evaporator core with clean water using the spray gun to remove all disinfectant residue. At least a two quart rinse is recommended.
17. Reach into the vehicle and turn the ignition to the "OFF" position and then reinstall the blower resistor.
CAUTION:
Blower resistor may be bot.
18. Dispose of disinfectant properly and rinse water runoff collected in the drain pan in an approved manner.
For vehicles repaired under warranty use
Labor Operation: T6235 Labor Time: 0.8 Hours
If debris needs to be removed from heater/evaporator case and the air inlet screen needs to be sealed, use an add time of .2 hour. If evaporator drain needs to be unclogged, use an add time of .2 hour.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
