How do you replace a heater hose fitting on a 3800 series engine?

To replace a heater hose fitting on a 3800 series engine, first, ensure the engine is cool and disconnect the negative battery cable. Drain the cooling system to avoid spills, then locate the fitting, which is typically on the intake manifold or engine block. Remove the old fitting using the appropriate tools, clean the threads, and install the new fitting with thread sealant if necessary. Finally, reconnect the hoses, refill the cooling system, and check for leaks.