Glow Plug Replacement: 2.0L TDI 16V (Articles)

Instructions for changing the glow plugs on a 2.0L pump-injector TDI engine with 16 valves, using the BRE engine code as an example. The BRE engine uses ceramic glow plugs.

Necessary tools:
- Torque wrench up to 20 Nm.
- 8mm open-end wrench with the ability to be attached to a torque wrench (in my case, a 12mm socket fit over the 9mm outer diameter of the open-end wrench), or a suitable spark plug wrench.
- Appropriate tool for the screws on the cylinder head cover, depending on the model.
- Screwdriver for bits, equipped with a magnet.
- Long, narrow flat-nose pliers.
- Roll of paper for cleaning (e.g., motor oil, dirt).
- If you have a date or visit coming up in the next few days, or if you want to please your wife: A pack of nitrile gloves.

Procedure:
1. Make sure the engine is properly warmed up. The glow plugs are best removed from the cylinder head while it's still hot.
Disconnect the crankcase ventilation and other hoses, loosen the upper timing belt cover, and remove the cylinder head cover.
3. Use pliers to disconnect the electrical connectors from the glow plugs and bend them aside.
4. Remove the glow plugs. It sounds simple, and it is, especially if defective glow plugs are replaced early. If you continue to drive with them, more and more combustion residue accumulates between the cylinder head and the glow plug that is no longer being heated, causing it to seize. In such cases, a glow plug can even break off when trying to remove it. There are special tools available for drilling out/removing broken glow plugs, but this carries some risk. Therefore, it's best to replace them immediately if they are defective.
5. Remove the spark plugs without dropping them into the cylinder head where they could get lost. I used a bit holder that has a magnet on its head to secure the bits. The magnet holds the spark plug firmly in place.
6. Screw in the new glow plugs. Caution: Handle ceramic glow plugs like raw eggs; if they fall on the floor, cracks may form. When tightening, always use a torque wrench and adhere to the specified torque. In my case, it was 10 Nm. The torque is essentially dependent on the thread of the glow plug (in my case, M. Glow plugs that are tightened too much will come loose again after a very short time, depending on the design. Therefore, work carefully so you don't have to replace the glow plugs again immediately. Why: Glow plug technical articles.
7. Clean the mating surface of the cylinder head cover. Install the cylinder head cover at a slight angle (crosswise) and tighten it in several steps to the specified torque. Reconnect the crankcase ventilation system, etc. Reattach the timing belt cover.

After replacing the glow plugs, you can often clear the error memory in many engine control units using software like VCDS or an OBD scanner and check if any new error codes related to the glow plugs appear.