Caution: Replace spark plugs only when the engine is cold or slightly warm. If the spark plugs are turned out on a hot engine, the threads of the light metal cylinder head may be stripped.
Before starting work, prepare all the necessary tools. Some spark plug manufacturers supply special tools to measure the spark plug gap.
- Candle wrench 16 mm, for example, HAZET 4766-1 or AUDI-3122B.
- If necessary, AUDI T40039 puller for ignition coils.
- Depending on the number of engine cylinders, the required number of spark plugs. Applicable spark plugs are listed in Specifications.
The best way to replace spark plugs is to buy new spark plugs in advance, adjust their gap, and replace each spark plug in turn. When buying candles, it is very important to choose exactly those candles that are designed for the engine of your car. Information about them is given in Specifications.
With new spark plugs on hand, let the engine cool completely before removing the old ones. During this time, you can inspect new spark plugs for defects and check spark plug gaps.
Security measures: Do not touch high voltage parts. Persons with a pacemaker should not carry out any work on the electronic ignition system.
Withdrawal
1. Turn off the ignition.
2. Remove the engine top cover, refer to Section Removal and installation of the upper engine cover / lower protection of the engine compartment / subframe.
3. Disconnect connectors (1) spark plugs (illustration - Engine 1.6 l).
4. Disconnect the connecting plugs (1) ignition coils (illustration - Engine 1.6 l).
5. Disconnect the rod ignition coils from the spark plugs, for example, with an AUDI T40039 puller.
Caution: Be sure to install the T40039 puller on the uppermost, thickest rib (arrow on accompanying illustration) ignition coils and pull up. If installed on the lower edge, it may be damaged.
Engine 2.0 l
1. Remove the bolts (1).
2. Disconnect connectors (2) ignition coils.
3. Remove the ignition coils (3), as on a 1.8 l engine, with spark plugs, for example, with a T40039 puller.
Engine 3.0 l
1. Remove the upper part of the air filter, refer to Section Removal and installation of the air filter.
2. Disconnect the coolant expansion tank from the holder and move it aside with the hoses attached.
3.Remove the screws (1). The accompanying illustration shows the right bank of cylinders.
4. Disconnect connectors (2) ignition coils (3).
5. Disconnect the ignition rod coils (3), like a 1.8 liter engine, from spark plugs, for example, using a puller T40039.
Engine 4.2 l
1. Remove the air filter.
2. Remove the left top cover of an impellent compartment.
3. Disconnect the coolant expansion tank from the holder and move it aside with the hoses connected.
4. Remove the screws (1). The accompanying illustration shows the right bank of cylinders.
5. Disconnect connectors (2) ignition coils.
6. Disconnect the ignition rod coils (3), like a 1.8 liter engine, from spark plugs, for example, using a puller T40039.
All engines
1. Remove the spark plugs using a suitable spark plug wrench, such as HAZET 4766-1 or AUDI. At the same time, make sure that the candle key does not warp. Otherwise, it may lead to the destruction of the ceramic insulator.
Examination
1. Compare the removed candle with those shown in the pictures in the Chapter Engine Electrical Systems, this will give you useful information about the general condition of the engine.
2. Check the electrode spacing with a probe. The illustrations show a spark plug with one ground electrode. The required gap value is given in Specifications.
Warning: New spark plugs usually have the electrode spacing set correctly.
3. To set the distance between the contacts, bend the corresponding ground electrode. To do this, tap on it from the side. When bending, rest a small screwdriver on the edge of the thread. Never lean on the center electrode, as this can be damaged.
4. Apply a small amount of copper anti-seize compound to the threads of the new spark plug.
Installation
Install the spark plug in the cylinder head and screw it in with your fingers until it stops, then tighten it with the head of the spark plug wrench.
Warning: To prevent the spark plug from being screwed in out of thread, place a small piece of rubber hose or plastic tubing over the spark plug shank. The flexible tube will work as a universal joint, ensuring that the spark plug is aligned with the spark plug socket, and if the spark plug starts to warp, the hose will slip on it, making it impossible to strip the threads.
If possible, use a torque wrench to tighten the spark plug to make sure it is installed correctly. The tightening force of the candles is given in Specifications. If a torque wrench is not available, turn new spark plugs 90°, used spark plugs 15°. Spark plugs that are too tight can damage the threads in the cylinder head when turning them out. In this case, the thread is repaired using UTC or Heli-Coil inserts.
1. Further installation is carried out in the reverse order of removal.
2. All engines except 1.6 L: Install the ignition coils with a slight twist. They must be clearly marked.
3. Engine 1.6 l: Connect the connectors. Then check the reliability of fastening wires and connectors.
4. Reinstall the engine top cover, refer to Section Removal and installation of the upper engine cover / lower protection of the engine compartment / subframe.
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