This Preliminary Information communication provides information to the technician the steps needed to diagnosis and repair vehicles with a noise can be heard from the dash area while the engine is running. Some vehicles may have a heater with reduced performance. Technician will gain access to the heater core inlet hose and remove it. There will be an inlet screen installed in the core that may be plugged with debris, causing this noise. If debris is present clean the screen or replace it. The vehicles coolant system will need to be flushed if debris if found. If a lot of debris is found in the inlet screen, back flush the heater core as well. Do not replace the heater core for a noise issue.
