Thermostat Inspection (4.0L) - Mazda B-Series 1997 Workshop Manual

E3
THERMOSTAT
INSPECTION
Thermostat
Mechanical
--
I. Visually check that the thermostat valve is airtight.
2. Place the thermostat and a thermometer in water.
3. Heat the water and check the following:
Initial-opening temperature: 89°C (192°F)
Full-open temperature: 100°C (21 2°F)
Full-open lift: 3.2mm (0.126 in) minimum.
4. If the gasket surface of the thermostat is damaged,
WE1 028-A 4BUOE3-022
replace the thermostat.
Electrical
Note
This test should be performed at temperatures less
than 37.8"C (100°F) ambient air.
1. Hook up the New Generation Star (NGS) tester. (Refer to
Section FT.)
Note
For an accurate test reading the engine cooling fan
must be running.
2.
Make sure AIC switch is in OFF position.
3. Place the vehicle in Park (P) or Neutral (N).
4. Start the vehicle and allow the engine to run for 2 minutes.
5. Record the Engine Coolant Temperature (ECT) sensor
voltage reading.
6. Record the ECT sensor voltage reading every
60 seconds.
7. When ECT voltage reverses direction trend or changes
slightly (0.03 volt or less), thermostat has opened.
8. Refer to the chart for the voltage and corresponding
temperature to verify thermostat operation.
ME1040-A
(1) If the opening voltage is between 0.75 volts (82.2"C
(180°F)) and 0.5 volts (90.6"C (195"F)), the
thermostat is operating.
(2) If the operation voltage is not within this range, replace
the thermostat.
Coolant I ECT
Temperature "C
{ O F )
PID Volts
21.7 {71)
42.8 (109)
70.6 {I 59)
.
-
82.2 {I 80)
90.6 {I 95)
96.7 {206)
105.1 (221)
3.00
2.01
-
1.01
0.75
-
. -
-
0.59
-
-
0.50
0.40