HEATING SYSTEM TROUBLESHOOTING CAT. U, NO. 93-04
Article Text (p. 8)
1983 Mazda RX7
For www.iluvmyrx7.com
Copyright © 1998 Mitchell Repair Information Company, LLC
Monday, August 27, 2001 06:36AM
1. Drain the engine coolant from the radiator.
2. Remove the thermostat from the thermostat housing.
3. Visually inspect the coolant passages and thermostat housing
for any casting debris.
4. Feel around inside the thermostat housing for any foreign
materials, especially in the area around the heater pipe outlet.
If present, remove any casting sand or debris which may be
blocking the coolant passages or causing the thermostat to
stick open.
5. Verify the operation of the thermostat using the appropriate
workshop manual.
NOTE: In addition to the procedure to check for proper thermostat
opening the following check must be performed to ensure the
thermostat is closing properly. When the thermostat has
opened fully continue to bring the water to a boil. When the
water has reached a boil remove the thermostat from the
water and set it on the work bench. Closely watch as the
thermostat begins to close and that it closes smoothly and
does not hang up.
6. If the thermostat fails either of the above tests, Replace it.
7. Using a filter, refill the radiator with engine coolant.
Recommended Climate Control System Operation
If all systems check out O.K., or through reviewing the Customer
Comment Sheet it is determined the system is being operated
incorrectly, instruct the customer on the proper system operation
using the operating guidelines listed below.
Item 1 - Air Intake Selector (Fresh/Recirculation)
This selector controls the source of air that enters the vehicle.
Usually, for heating or defrosting the air intake selector should be
in the "Fresh" or outside air mode. However, if there is a heavy
presence of exhaust fumes in the surrounding area it may be necessary
to switch to the "Recirculation" mode. It is important to remember
to return to the "Fresh" mode because humidity may build up in the
"Recirculation" mode causing the windows to fog up. See Fig. 5.
Another method to help reduce humidity within the vehicle is to use
the Air Conditioning system. Its dehumidifying characteristics can be
taken advantage of in any situation.