Service manual

Webasto Diesel Cooker X 100 5 Updating and repair

506

5.4 Glow plug

The glow plug consumes approximately 8 A of power

during the glowing stage. The length of the glowing

phase is the time stated in the parameters. The

temperature of the glow plug rises extremely quickly.

As you can see from Fig. 5, the tip of the plug reaches

850°C in twenty second’s time. (The glow plug we

have used is in the 2

generation category.)

Malfunction:

The glow plug may experience a malfunction as a

result of thermal overload. In this case, the resistance

wire will either break or short circuit with the shell of the

glow plug.

Installation:

If you are only going to change the glow plug, make

sure you are careful in connecting the + wire. The

largest permissible tightening torque for the mounting

is 5 Nm. When connecting the mounting nut, you

must hold on to the bottom nut (1) to keep the

inner parts of the glow plug from becoming

damaged.

Testing:

To see if resistance wire is broken, measure the

resistance between the + and – terminals with a

circuit analyzer. There will be no resistance if the

plug is broken. The resistance between the

terminals of an undamaged plug is approximately 1

ohm. In case of a short circuit, measuring the

resistance will not uncover the malfunction because

there is a 1 ohm resistance in the wires of the circuit

analyzer alone. In this case, you can hook the glow

plug up to a 12 V power supply (remember the fuse!)

and monitor the heating of the tip of the glow plug. The

tip should turn red within 20 seconds, if the glow plug

is working as it should.

Protect your eyes and be

exremely careful when connecting

the glow plug to the power supply.

A defective glow plug may spatter

melted metal through the shell.