Here's a general overview, but this is not a comprehensive guide. You'll need a repair manual specific to your 1994 Cadillac model (Sedan DeVille, Fleetwood, etc.) for precise instructions and diagrams:
1. Safety First: Disconnect the negative battery cable before starting any work. Allow the engine to cool completely.
2. Locate the Heater Core Hoses: These hoses are usually located near the firewall, where the heater core is situated within the dashboard. One hose will be hot (supply) and the other will be cool (return). Your repair manual will show their exact location.
3. Drain the Coolant: Drain some coolant from the system to reduce the mess. The drain plug location will also be in your repair manual.
4. Disconnect the Hoses: Carefully disconnect the two heater core hoses at their connections. Be prepared for coolant spillage.
5. Bypass the Heater Core: Use appropriately sized hose clamps and new lengths of hose (matching the original hose diameter and material) to connect the two hoses together, bypassing the heater core entirely.
6. Reconnect the System: Re-connect all hoses and clamps securely.
7. Refill the Coolant System: Carefully refill the coolant system with the correct type and amount of coolant for your vehicle, as specified in your owner's manual. Bleed the system of any air pockets, as air in the system can cause overheating.
8. Test: Reconnect the battery and run the engine, carefully monitoring the temperature gauge and checking for any leaks.
Again, this is a simplified overview. Attempting this without a repair manual specific to your 1994 Cadillac model is strongly discouraged. The procedure can vary significantly depending on the specific model and engine type. A repair manual will provide detailed diagrams and instructions to ensure the job is done correctly and safely. If you are not comfortable performing this repair yourself, consult a qualified mechanic. Bypassing the heater core is often a temporary fix and may indicate a more serious problem with the heater core itself.
