A/C - Insufficient Heater Output at Idle

Condition

80 07 05

Sept. 14, 2007

2011762 Supersedes T.B. Group 80 number 07-01 due to addition of coolant reservoir and warranty table information change.

Customer States Heater Output is Sufficient while Driving But is Reduced When Idling

While driving heat output from HVAC will warm cabin area sufficiently when setting is at high, med, or low, but when idling, heat output greatly diminishes.

For example, output temperature from center vent while driving is approximately 160°F (71°C), but while sitting at idle, output temperature decreases to approximately 90°F (32°C).

Technical Background

May be caused by a small amount of air in cooling system.

Production Solution

Improved coolant reservoir as of VIN:

1C_7M 518233

1Y_7M416166

Service

Install improved coolant reservoir Part No. 1C0121407 E, see Repair Manual Group 19 Engine - Cooling system, in ElsaWeb.

After installation:

^ Purge the air from coolant system using the VAS 6096 "Cooling System Charge Unit" as follows.

WARNING
Prior to working on any cooling system, always review and follow all Notes, Tips, and Warnings in Group 19 - Engine - Cooling system.

Tip:

Illustrations used in this Bulletin are from documentation included with the VAS 6096 "Cooling System Charge Unit".

Procedure:





^ Install the VAS 6096 onto the Cooling System using the appropriate adapters (fig. 1).





^ Install the VAS 6096 onto the fill tank using the appropriate adapter (fig. 2).





^ Install air compressor hose (fig. 4).





^ Verify both valves are in the closed position (fig. 5).





^ Open valve on air hose side (fig. 6)





^ Open the valve on the supply side for 2 seconds to purge the air from the hose (fig. 7).

^ Open valve on air hose side.

Leave valve open for ten minutes.

^ Close the valve on the air hose side and open the valve on the supply side.

^ Leave valve open on reservoir side while monitoring the gauge.

^ Wait for the gauge to settle at it lowest point and close the valve.

^ Remove VAS 6096 from vehicle.

^ Adjust coolant level as necessary.

^ Allow engine to idle for 5 minutes and re-check heater temperature output.





Warranty





Required Parts and Tools

Additional Information

All part and service references provided in this Technical Bulletin are subject to change and/or removal.

Always check with your Parts Dept. and Repair Manuals for the latest information.