Aerostar 2WD V6-245 4.0L (1990)
Use the following "Cooling System Diagnosis" procedure to diagnose a cooling system that may not be reaching normal operating temperature. Follow
the "Thermostat Diagnosis" procedure to determine if the thermostat may be at fault. Check the thermostat without removing it from the vehicle by using
Rotunda Service Coolant Temperature Monitor Harness 007-00064.
A new cooling system diagnosis procedure has been developed for engines that do not reach normal operating temperature. A new thermostat diagnosis
procedure also has been developed, using a new service coolant temperature monitor harness.
NOTE:
THIS PROCEDURE WILL DIAGNOSE ONLY COOLING SYSTEMS THAT MAY NOT BE REACHING NORMAL OPERATING
TEMPERATURE. IT WILL NOT DIAGNOSE A THERMOSTAT THAT CAUSES AN ENGINE OVERHEAT CONDITION.
NOTE:
THE ESCORT/TRACER SPECIFIC APPLICATION FOR THIS ARTICLE IS AS FOLLOWS:
^
1983-1990 Escort 1.9L and 1.6L
^
1991-1994 Escort 1.9L
^
1991-1994 Tracer 1.9L Only
THERMOSTAT DIAGNOSIS
NOTE:
DISCONNECTING THE POWERTRAIN CONTROL MODULE (PCM) TO ATTACH A BREAKOUT BOX OR AN EEC IV MONITOR WILL
ERASE THE ADAPTIVE LEARNING FROM MEMORY AND MAY "HIDE" A DRIVE CONCERN TEMPORARILY UNTIL THE ADAPTIVE
LEARNING IS RE-LEARNED.
NOTE:
THIS PROCEDURE IS MOST ACCURATE IF PERFORMED INDOORS AT LESS THAN 100~F (38~C) AMBIENT TEMPERATURE. THIS TEST
MAY BE PERFORMED WITH OR WITHOUT THE HOOD OPEN AND WITH THE ENGINE WARM OR COLD.
CAUTION:
ALWAYS VENT THE EXHAUST TO THE OUTSIDE WHEN PERFORMING THIS TEST.
1.
Check the coolant level in the radiator and coolant recovery reservoir.
2.
With the key in the "off" position, proceed as follows:
a.
Remove the engine coolant temperature (ECT) sensor harness connector.
b.
Attach Rotunda Service Coolant Temperature Monitor Harness 007-00064 as a jumper between the PCM and the ECT.
c.
Attach Rotunda 73 Digital Multimeter 105-00051 or equivalent to the thermostat monitor harness. Voltage values (0-5vdc) may now be
