Heating Output, Checking: Notes

WARNING: This page is about a different car, the 2016 Volkswagen Beetle, 2015 Volkswagen Beetle, 2014 Volkswagen Beetle, 2013 Volkswagen Beetle, and 2012 Volkswagen Beetle. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If the coolant system is not bled completely after being filled, then air can get into the heater core. This will reduce the heating output and noises may result or the customer may complain there are different air temperatures coming out of the driver side and front passenger side vents.

Corrective action for poor heating output or noises from coolant circuit

-- Perform a lengthy test drive at high engine speed (at least 10 minutes, engine speed above 2500 rpm). Select a low gear during the test to prevent excessive vehicle speed.

-- If customer complains of poor heating output at certain engine speeds, check the integration of the heater core for the heater into 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. Refer to Coolant Hose Connection Diagram (CJAA, CVCA) , CONNECTION DIAGRAM - COOLANT HOSES (CPLA, CPPA, CPKA, CPRA) , COOLANT HOSE CONNECTION DIAGRAM (CCTA, CBFA) or COOLANT HOSE CONNECTION DIAGRAM (CBTA,CBUA) .

-- In vehicles with a parking/auxiliary heater, check the activation of the Recirculation Pump -V55- on the parking heater and make sure that the parking heater is incorporated inside the coolant circuit.

Requirements for reaching maximum heating performance

The coolant circuit is bled in stages. Refer to COOLANT, DRAINING AND FILLING .
All air ducts, covers and seals OK and properly installed.
Check that the air flow through dust and pollen filter is not obstructed by dirt. Refer to DUST AND POLLEN FILTER .
The engine is warm.
The release cable and the operating lever on the temperature flaps are OK.
The engine thermostat is OK. .
The foam seal on the heater core is OK. Refer to HEATER CORE .
On vehicles with a Diesel engine, the function of the Auxiliary Heater Heating Element -Z35- and the activation of the Heater Control Module -J65- is OK. Perform "Guided Fault Finding" using the Vehicle Diagnostic Tester (on the auxiliary air heater) in Parking Heater (checking the auxiliary heater).
On vehicles with a gasoline engine, the activation of the engine control module from the Heater Control Module -J65- is OK.