Mustang GT V8-4.6L SOHC VIN X (1998)
Heater Core: Testing and Inspection
WARNING: CARBON MONOXIDE IS COLORLESS, ODORLESS AND DANGEROUS. IF IT IS NECESSARY TO OPERATE THE
ENGINE WITH THE VEHICLE IN A CLOSED AREA SUCH AS A GARAGE, ALWAYS USE AN EXHAUST COLLECTOR TO VENT
THE EXHAUST GASES OUTSIDE THE CLOSED AREA.
The heater core is an all-aluminum core which has two rows of flat tubes to maximize engine coolant flow. It is located in the A/C evaporator housing in
the passenger compartment under the instrument panel.
1. Inspect for visible evidence of coolant leakage at the heater water hose to heater core attachments. A coolant leak in the heater water hose could
follow the heater core tube to the heater core and appear as a leak in the heater core.
NOTE: Testing of returned heater cores reveals that a large percentage of heater cores are good and should not have been replaced. If a heater
core leak is suspected, perform Plugged Heater Core component test before removing the heater core. Perform a system inspection by checking the
heater system thoroughly:
2. Check integrity of the heater water hose clamps.
3. Spring-type clamps are installed as original equipment. Installation and over-tightening of non-specified clamps can cause leakage at the heater
water hose connection and damage the heater core tube.
Plugged Heater Core
Check to see that the engine coolant is at the proper level. Start the engine and turn on the heater. When the engine coolant reaches operating
temperature, feel the heater core outlet hose to see if it is hot. If it is not hot, the heater core may have an air pocket or may be plugged, or the
thermostat is not working properly.
Pressure Test
Use Rotunda Radiator Pressure Tester 014-R1072 or equivalent to perform pressure test.
1. Drain the coolant from the cooling system.
