← BX
Autopapyrus · Citroën BX 1.9 D (1991)
https://autopapyrus.com/guides/citroen/bx/glow-plug-replacement/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Citroën BX 1.9 D (1991): Glow Plug Replacement

On the 1.9 D diesel (XUD9 family), the four glow plugs are installed in the cylinder head, one per cylinder, and are fed from a common bus bar. The main risks are a seized or broken-off plug and damage to a terminal. Do the work on a completely cold engine, and always soak seized plugs with penetrating oil before unscrewing them.

Difficulty: Easy Time: 1-1.5 hours Steps: 12 Tools: Thin-wall socket or 12 mm wrench (for threading in the plug), 8-10 mm wrench for terminals, multimeter or test lamp, copper grease, penetrating oil (WD-40 or equivalent), low-range torque wrench, clean rag.

Part

  • 🔩 Glow plugs for the XUD9 diesel (1.9 D, 68 hp), 4 pieces, rated voltage 11 V, per the catalog listing for the XUD9 engine. Known manufacturers: Bosch, Champion, NGK, Beru. If needed, a separate bus bar or jumper and terminal lock nuts may also be required

Step by step

12 steps
  1. Let the engine cool down completely. Shut off the engine, remove the key, and disconnect the negative battery terminal.
  2. Locate the glow plugs: they are threaded into the cylinder head on the intake side, and each one has a terminal connected to the common power bus bar. Remove any plastic covers and shields that are in the way, if fitted. Take a photo of how the wires and the bus bar are arranged.
  3. Test the old plugs before removal: apply battery voltage to each one through a multimeter or test lamp, or measure the resistance. A working plug has low resistance, from a few tenths of an ohm to a few ohms. An open circuit means the plug has failed. This tells you which plug to replace, although on a car of this age it makes sense to replace the whole set.
  4. Remove the terminals and the bus bar. Undo the terminal nuts carefully, without turning the plug terminals, otherwise the internal contact can break. Clean any oxidized contacts.
  5. Clean the area around each plug with compressed air or a brush so that carbon deposits and dirt don't fall into the cylinder. Soak the threads with penetrating oil and wait 10-15 minutes.
  6. Unscrew the plugs one at a time, without jerking. If a plug turns hard, work it half a turn back and forth, add more oil, and repeat. Do not apply sudden force: the plug can snap and leave its tip in the cylinder head. In that case it needs to be extracted, and it is best to go to a repair shop.
  7. Inspect the plug seats. If necessary, clean the threads in the head, but only with a careful thread chaser (tap), and don't let any chips fall into the cylinder.
  8. Apply a thin layer of copper anti-seize grease to the threads of the new plugs. Do not apply grease to the contact terminals or connectors.
  9. Thread each plug in by hand until it stops, then tighten it with a torque wrench. A typical torque for glow plugs of this type is 10-20 N·m (7-15 lb-ft); the exact value depends on the plug model and is given on the packaging or in the manufacturer's data sheet. Do not overtighten, or the plug may break or the threads may be damaged.
  10. Install the bus bar and terminals, and tighten the terminal nuts without excessive force so you don't strip the threads on the terminal post. Make sure the bus bar does not touch the body metal or the cylinder head.
  11. Reconnect the negative battery terminal. Turn the ignition on and check that the glow plug light comes on and goes off, and that the plugs heat up. If you have a multimeter, measure the current draw, which should be roughly the same on all four plugs.
  12. Start the engine. A cold start should happen without long cranking and without thick white smoke. After warm-up, check for exhaust smell or smoke around the plugs, which is a sign of a leaking seat.

Common mistakes and warnings

  • Do not install plugs with a non-standard voltage (for example, 6 V or 12 V instead of the standard 11 V): they will burn out or will not heat enough. Before buying, compare the length and diameter of the working part with the old plug. If a plug will not unscrew or has broken off, do not keep forcing it, and go to a repair shop: a broken piece in the cylinder head is removed with a special tool.