Cooling System - Coolant Leaks/Poor Heater Output
19 Coolant leak or no heat in passenger compartment from HVAC19 10 06
2009949/6
June 18, 2010
Supersedes Technical Service Bulletin Group 19 number 09-01 dated March 5, 2009 for reasons listed below.
Affected Vehicles
Condition
^ Customer concern of loss of coolant, but no leak in cooling system can be found.
^ Customer concern of no heat or noticeable drop in heat output in passenger compartment from HVAC system when engine at idle.
Technical Background
Both concerns may be caused by a coolant leak from plastic plug.
Plug is installed in engine cylinder block near connection for thermostat housing (Figure 2).
Production Solution
Optimized coolant plug.
Service
Other than loss of coolant, a leaking plug can cause air to enter into the cooling system and reduce the effectiveness of the passenger compartment heating system.
1. Ensure engine is cold (below 32°F / 0°C). The leak from this plug usually occurs only when the engine is cold. If cooling system is tested for leaks with engine warm or hot, leaks from this plug may not be detected.
2. Check for leaks according to ElsaWeb Repair Manual >> Engine Mechanical >> 19 Engine Cooling, Cooling system, checking for leaks.
3. Carefully inspect area where plug is located.
Tip: Coolant leak from this plug can be sometimes misdiagnosed as a leaking coolant thermostat housing. Always carefully inspect suspected areas to detect the actual source of the leak.
If the plug is found to be leaking:
1. Remove and replace the plug.
2. Remove sound insulation below engine.
3. Drain coolant. (See ElsaWeb Repair Manual >> Engine Mechanical, 19 Engine Cooling, >> Cooling system, draining and filling.)
4. Remove upper engine cover.
5. Unfasten coolant reservoir and move aside.
^ Electrical connector of coolant level sensor must be unplugged.
^ It is not necessary to remove coolant hoses from coolant reservoir.
6. Remove oil dipstick bracket bolts (2x).
7. Carefully remove upper dipstick tube (orange plastic). Ensure that the O-ring on lower steel tube is not lost when tube is removed.
8. Remove bolt from plastic plug.
9. Remove plastic plug from engine block.
10. Install a new plastic plug and secure with bolt to engine block. Fastener torque = 23 Nm.
11. Reassemble dipstick tube and coolant reservoir.
12. Use the VAS 6096/1 to refill and bleed the cooling system. (See ElsaWeb Repair Manual >> Engine Mechanical >> 19 Engine Cooling >> Cooling system, draining and filling for details and approved coolant antifreeze.)
13. When refilling engine with coolant:
^ Always ensure that any trapped air is bled out of cooling system (including heater core).
^ Recheck for leaks on cooling system. (See ElsaWeb Repair Manual >> Engine Mechanical >> 19 Engine Cooling >> Cooling system, checking for leaks).
^ Reinstall sound insulation below engine.
^ Reinstall upper engine cover.
Warranty
Required Parts and Tools
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.