Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1990LUMINA APV V6-191 3.1LREPAIR AND DIAGNOSISHEATING AND AIR CONDITIONINGHEATER CORESERVICE AND REPAIR
1990 Chevrolet Lumina APV V6-191 3.1L
Heater Core: Service and Repair
1990 Chevrolet Lumina APV V6-191 3.1LSECTION Service and Repair
1. Disconnect battery ground cable.
2. Drain cooling system, then remove heater inlet and outlet hoses.
3. Using compressed air, blow air through heater core nipples to remove coolant from heater core.
4. Remove right side sound insulator panel, then remove glove box to access heater core cover retaining screws.
5. Disconnect black vacuum source hose connected to vacuum actuator solenoid input port.
6. Disconnect instrument panel electric harness connector to solenoid assembly.
7. Remove six heater core cover retaining screws, then lower cover to vehicle floor.
8. Remove heater core.
9. Reverse procedure to install.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.