Visibility: defroster/defogger/hvac system: heater core
- Component
- Visibility: defroster/defogger/hvac system: heater core
- Manufacturer
- BAYERISCHE MOTOREN WERKE
- Vehicles affected
- 375,000
- Reported to NHTSA
- 1993-02-01
- Owners notified
- 1993-06-04
Defect description
THE MALFUNCTION OR FAILURE OF A COOLANT SYSTEM COMPONENT RESULTS IN SIGNIFICANTLY INCREASED COOLANT TEMPERATURE AND A RESULTING INCREASE IN SYSTEM PRESSURE.
Safety risk
VEHICLES OPERATED UNDER THIS INCREASED COOLING SYSTEMPRESSURE CONDITION CAN SUFFER DAMAGE OR FAILURE OF PARTS OF THE COOLING SYSTEMSUCH AS (1) LEAKAGE FROM A COOLANT HOSE, (2) LEAKAGE OF THE RADIATOR OREXPANSION TANK, (3) DISCONNECTION OF A HOSE FROM A PIPE OR A FITTING, AND (4)CRACKS IN THE HEATER CORE END PIECE RESULTING IN COOLANT LEAKAGE. IN SOME CASES,BOILING COOLANT CAN CONTACT THE LOWER RIGHT LEG OF THE DRIVER RESULTING INBURNS. ALSO, ESCAPING COOLANT IN THE PASSENGER COMPARTMENT CAN CAUSE VAPORFOGGING OF THE INTERIOR SURFACE OF THE WINDOWS, REDUCING DRIVER VISIBILITY.
Manufacturer remedy
DEALERS WILL INSTALL A THERMOSTATIC BYPASS VALVE IN THE ENGINE COMPARTMENT TO CONTROL COOLANT TEMPERATURE IN THE HEATER CORE. ALSO, A NEW DESIGN RADIATOR CAP WILL BE INSTALLED, TO CONTROL PRESSURE AND PROVIDE GREATER COOLANT OVERFLOW IN THE EVENT OF OVERHEATING.