Glow Plug: Service and Repair
Glow Plugs
Special tools, testers and auxiliary items required
• Torque Wrench (5-50 Nm) (V.A.G 1331)
• Engine Bung Set (VAS 6122)
• Hose Clamp Pliers (VAS 6362)
• Socket Insert AF 12 for Glow Plugs 4-Cyl. TDI CR (VAS 6454)
• Follow the safety precautions when working on the diesel direct injection system. Refer to => [ Fuel System ] Fuel System.
• Follow the guidelines for clean working conditions. Refer to => [ Clean Working Conditions ] Clean Working Conditions.
Always follow these instructions before and during work.
Removing
• When removing the glow plugs, make sure no contaminants enter the fuel system and the glow plug bore.
• Seal off the connections in the fuel system using plugs from the engine bung set (VAS 6122).
Requirements
• The ignition is off.
• The engine must be cold.
Removing
- Remove the engine cover. Refer to => [ Engine Cover ] Engine Cover.
- Remove the protective strip, - item 1 - in the => [ Fuel System Component Overview ] Fuel System Component Overview, if equipped.
- Disconnect the connectors from the fuel injectors - A -, the exhaust pressure sensor 1 - B - and the fuel pressure sensor - C -.
- Remove the coolant line bolts - arrows - from the intake manifold and lay the line in front of the intake manifold.
- Remove the bolt - arrow - from the intake manifold for the fuel return line.
- Install the pliers (3314) with the groove - arrow A - on the upper collar of the connector - arrow B - and squeeze together lightly.
Position the pliers so they do not touch or damage the wire.
Only use suitable tools.
Other unsuitable tools can damage the connector.
If the connector is damaged when removing it, replace the complete wiring harness including the connector (a connector cannot be replaced separately).
- Carefully pull the connector off the glow plug in the - direction of the arrow - using the pliers (3314).
Do not pull abruptly on the connector.
Do not damage the connector wire.
Do not press the pliers together too firmly or the connector will be damaged.
The connector is surround by a protective sleeve. Replace the protective sleeve if it is damaged.
- Reposition the hose clamp - arrow - using the hose clamp pliers (VAS 362) and remove the line from the fuel rail.
- Before removing, clean the return line connection on the fuel injectors (for example using a commercially available detergent).
- Dry the return line connections.
- Cover the return line connections with a cloth.
- Remove the fuel return line connections from the fuel injectors. Pull them upward to release them - arrow -.
• Pay attention to cleanliness. Do not let any dirt to get into the disconnected return lines or into the connections for the fuel injection units.
- Reposition the hose clamp using the hose clamp pliers (VAS 6362) and remove the fuel return line.
- Reposition the hose clamp - 4 - using the hose clamp pliers (VAS 6362) and remove the fuel return line at the high pressure fuel pump.
- Seal the lines so that the fuel system is not contaminated by dirt, etc.
- Remove the fuel return lines and lay them in front of the intake manifold.
- Remove the glow plug wiring guide and lay it aside.
• When cleaning the glow plug bore, make sure no contaminants or cleaning solutions enter the connector contacts on the glow plugs.
• Do not clean the connectors with cleaning solutions or compressed air.
- Clean the glow plug bore in the cylinder head (contaminants must not fall into the cylinder).
• Extract large contaminants with a vacuum cleaner.
• Clean glow plugs with a commercially available detergent.
• Dry the glow plugs with compressed air.
• Then clean the glow plug bore with a cloth dampened with oil.
- Remove the glow plugs using the socket insert AF 12 for glow plugs 4-cyl. TDI CR (VAS 6454).
Installing
Install in the reverse order of removal. Note the following:
• When installing the glow plugs, make sure no contaminants enter the fuel system and the glow plug bore.
• Only remove the sealing plugs right before installing the fuel return line.
• Make sure lines connections are securely fastened.
- Install the glow plugs using the socket insert AF 12 for glow plugs 4-cyl. TDI CR (VAS 6454).
• Tightening specification: 12 Nm.
- Secure the fuel return line to the intake manifold.
• Tightening specification: 8 Nm.
- Guide the center terminal of the connector - arrow A - into the glow plug socket - arrow B - by hand.
- Press the glow plug connector - 1 - on by hand until it engages.
- Install the fuel return line.
- Check the Engine Control Module (ECM) Diagnostic Trouble Code (DTC) memory and erase all faults stored in the DTC memory. Refer to the vehicle diagnostic tester.