Ranger 2WD V6-245 4.0L VIN X SFI (1997)
Temperature Gauge: All Technical Service Bulletins
Cooling System - Erratic Temperature Gauge/Noise
Article No.
99-23-8
11/15/99
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GAUGE - TEMPERATURE GAUGE FLUCTUATION
AND/OR "KNOCKING/THUMPING" NOISE FROM
COOLING SYSTEM - 4.0L OHV ENGINE
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COOLING SYSTEM - PULSATING COOLANT
FLOW - NOISE - "KNOCKING/THUMPING"-
AUDIBLE IN PASSENGER COMPARTMENT - 4.0L
OHV ENGINE
^
NOISE - "KNOCKING/THUMPING" - COOLING
SYSTEM - AUDIBLE IN PASSENGER
COMPARTMENT - 4.0L OHV ENGINE
FORD:
1995-2000 EXPLORER, RANGER
This TSB article is being republished in its entirety to include 2000 model year vehicles and to provide Service Part(s) and Labor Time information.
ISSUE
A temperature gauge fluctuation and/or a "knocking/thumping" noise may be audible in the passenger compartment on some vehicles. This noise is most
pronounced with the engine at normal operating temperature. The noise is caused by steam formation in the cooling system. The noise is then transmitted
through the heater hoses and heater core.
ACTION
Install a Coolant By-Pass Kit. This increases coolant flow which reduces steam formation. Refer to the following Diagnostic and Service Procedure for
details.
DIAGNOSTIC AND SERVICE PROCEDURE
1.
Check for excessive exhaust system restrictions. A restricted exhaust could elevate cooling system temperatures.
2.
If dash-mounted cooling temperature gauge fluctuates, check that gauge and sending unit are functioning properly.
3.
Check for restrictions or kinks in the radiator or heater hoses.
4.
Pressure check cooling system for leaks.
5.
Confirm proper Engine Coolant Temperature (ECT) sensor signal to EEC-V processor.
6.
Check for correct 50/50 coolant mix. Verify that freezing point is -37°C (+/- 15°C) or -35°F (+/- 5°F).