Heating Performance, General Information

Heating Performance, General Information

Special tools, testers and auxiliary items required

• Diagnostic operation system (VAS 5051 A) (or Vehicle Diagnosis and Service System (VAS 5052) ).

• If coolant circuit is not completely bled after filling, air may accumulate in heater core of A/C unit, thus reducing heating performance of A/C system, additional noises may occur or customer may complain of different air temperatures flowing out of vents at driver's side and front passenger's side at the same setting.

Corrective action:

- Perform long road test at increased engine speed (at least 10 minutes, engine speed greater than 2500 RPM). Select a low gear during the test to prevent excessive vehicle speed.

- If customer complains of poor heating performance at specific engine speeds, check incorporation of heater core in A/C system in the coolant circuit. If both coolant hoses (supply and return) of engine are interchanged, coolant is flowing in the wrong direction through the heater core.

• Requirements for performing the heat output test, refer to => [ Heat Output Test Requirements ] Heat Output Test Requirements.

• Heating performance, checking => [ Heating Performance, Checking ] Heating Performance, Checking.