Here's a general outline of the process. Note: Specific locations of hoses and clamps may vary slightly depending on the engine and configuration of your truck. Consult a repair manual specific to your 1994 S-10 model for precise locations and diagrams.
1. Safety First: Ensure the engine is completely cool before starting. Wear safety glasses.
2. Locate the Heater Hoses: These are usually rubber hoses located near the firewall, connecting to the heater core inlets and outlets. One hose will be a hot supply line from the engine, and the other a return line to the engine.
3. Drain the Coolant: Slightly open the radiator drain valve to allow some coolant to drain. This will minimize spillage when disconnecting the hoses.
4. Disconnect the Heater Hoses: Carefully disconnect the two heater hoses from the heater core. Use pliers or a hose clamp tool to loosen and remove the clamps. Have a container ready to catch any spilled coolant.
5. Bypass the Heater Core: You'll need two short lengths of hose, ideally the same diameter as the heater hoses, and two hose clamps for each connection. Connect one end of each short hose to one end of the disconnected heater hoses. Secure the connections tightly with the hose clamps.
6. Reconnect the Bypassed Hoses: Connect the other ends of the short hoses together, again securing them tightly with hose clamps. Make sure the connections are secure and leak-free.
7. Refill the Coolant System: Carefully refill the radiator and coolant reservoir with the proper 50/50 mixture of coolant and distilled water (check your owner's manual for the correct type).
8. Check for Leaks: Carefully check all connections for leaks, especially after running the engine for a short time. Tighten any loose clamps as needed.
9. Bleed the Air from the System: After refilling, run the engine and let it idle for a few minutes. Check the coolant level and add more as needed. Make sure the system is properly bled to remove any air pockets.
Again, this is a temporary solution. Driving with the heater core bypassed means you'll have no heat in the cabin, which can be dangerous in cold weather. Repairing or replacing the heater core is the recommended solution. This process can be messy and requires some mechanical aptitude. If you're not comfortable performing this repair, seek the assistance of a qualified mechanic.
