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Mazda RX7. Manual - part 75

HEATING SYSTEM TROUBLESHOOTING CAT. U, NO. 93-04

Article Text (p. 5)

1983 Mazda RX7

For www.iluvmyrx7.com

Monday, August 27, 2001 06:36AM

Fig. 2: Diagnostic Flow Chart

CHECK SHEET

Heater concern

Item 1: Measuring Vent Outlet Air Temperature

1. Place transmission in park or place manual transmission in
neutral and set the parking brake.

2. Start the engine and let idle until the engine reaches normal
operating temperatures.

HEATING SYSTEM TROUBLESHOOTING CAT. U, NO. 93-04

Article Text (p. 6)

1983 Mazda RX7

For www.iluvmyrx7.com

Monday, August 27, 2001 06:36AM

3. Adjust the climate controls to the following settings:

Function ............. Bi-level
Temperature .......... Max. hot
Fan speed ............ 2
Recirculate/fresh .... Fresh

4. Raise the engine speed to 2000 rpm and hold for ten minutes.

5. Measure the vent outlet air temperature.

NOTE: The thermostat will cycle after the engine has reached
operating temperatures. Measure outlet air temperature
several times over a ten minute period to attain the high
temperature reading (thermostat closed).

Item 2 - Air Leakage

A. Interior Components

1. Remove the lower kick panel on passenger side.

2. Remove the glove box.

3. Adjust the climate controls to the following settings:

Function ................. Defrost
Temperature .............. Max. hot
Fan speed ................ 4
Recirculation-fresh ...... Fresh

4. Check for leakage between blower unit and cooler unit (air
duct).

5. Check for leakage between cooler unit (air duct) and heater
unit.

NOTE: Air duct is present only on vehicles not equipped with air
conditioning.

B. Engine compartment

1. Turn off the engine.

2. Raise the hood and visually inspect the following for proper
sealing:

* A/C drain grommet
* A/C pipes where they enter the cooling unit at the firewall.
* Heater pipes where they enter the firewall.
* All body harnesses that pass through the firewall.
* Speedometer cable.

HEATING SYSTEM TROUBLESHOOTING CAT. U, NO. 93-04

Article Text (p. 7)

1983 Mazda RX7

For www.iluvmyrx7.com

Monday, August 27, 2001 06:36AM

NOTE: Do not perform the above checks with the engine running.

Item 3 - Link and Wire Adjustment

1. Remove the kick panel on the passenger side of the vehicle.

2. Remove the glove box.

3. Place the transmission in park or set manual transmission in
neutral and set the parking brake.

4. Start the engine and allow to idle.

5. Set the climate controls to the following settings:

Temperature ........... Max. hot
Recirculation-fresh ... fresh

6. Using Figs. 3 and 4 for reference, ensure the linkages are
adjusted properly.

Fig. 3: Blower Unit Linkage Adjustment

Fig. 4: Heater Unit Linkage Adjustment

Item 4 - Coolant By-passing the Thermostat/Thermostat Stuck

HEATING SYSTEM TROUBLESHOOTING CAT. U, NO. 93-04

Article Text (p. 8)

1983 Mazda RX7

For www.iluvmyrx7.com

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.

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