Removal
Caution: If the glow plug system has just been running or the engine has just been turned off, the glow plugs will be very hot.
1. Disconnect the negative battery terminal.
2. Remove the air intake duct system and disconnect the crankcase ventilation hose from the oil filler neck.
3. Unscrew the fastening nut (indicated by the arrow) current bus to the glow plug. Note that the supply wire is connected to the current bus on the glow plug of cylinder #2.
4. If necessary, move any pipes and wires to the side to improve access to the glow plug being removed.
5. Unscrew the glow plug and remove it from the cylinder block.
Examination
1. Check each glow plug for mechanical damage. Burnt or broken glow plug tips may be caused by poor fuel spray from the injector. If such damage is present, the fuel injectors must be checked and replaced if necessary.
2. If the glow plugs are not mechanically damaged, check their electrical resistance, which should be less than 1 Ohm.
3. The glow plugs can be tested for efficiency by applying 12 volts to them. They should heat up evenly and within the required time interval.
4. In this case, it is necessary to observe the following precautions:
- hold the glow plug with a special clamp or pliers;
- the glow plug power supply circuit must have a fuse;
- after checking, the glow plug should cool for several minutes.
5. A glow plug in good condition heats up to the working tip turning red within 5 seconds. If it heats up longer or heats up in the middle part rather than at the end of the plug, the plug is faulty and should be replaced.
Installation
1. Installation is carried out in the reverse order of removal.
2. In this case, the threaded part of the spark plug must be lubricated with a copper-based non-stick compound.
Source available here [PeugeotBook.ru]