Heater Core Inspection: Notes
WARNING:
- Carbon monoxide is colorless, odorless and dangerous. If it is necessary to operate the engine with the vehicle in a closed area such as a garage, always use an exhaust collector to vent the exhaust gases outside the closed area.
NOTE:
- Testing of returned heater cores reveals that a large percentage of heater cores are good and did not require replacement. If a heater core leak is suspected, the heater core must be tested by following the plugged heater core component test before the heater core pressure test. Perform a system inspection by checking the heater system thoroughly as follows:
Inspect for evidence of coolant leakage at the heater hose to heater core attachments. A coolant leak in the heater hose could follow the heater core tube to the heater core and appear as a leak in the heater core.
Spring-type clamps are installed as original equipment. Installation and overtightening of non-specification clamps can cause leakage at the heater hose connection and damage the heater core.
Check the integrity of the heater water hose clamps.