Replacing spark plugs (VW Passat B5)

Spark plugs are replaced during scheduled maintenance.

If you ever have to replace spark plugs outside of routine maintenance, keep the following in mind.

Spark plugs and the entire ignition system as a whole are selected for this engine, and this helps to reduce the amount of harmful substances in the exhaust gases.

To avoid engine failures, reduced engine power, poor throttle response, increased emissions and interference with radio reception, only use spark plugs recommended by Volkswagen for this engine. Particularly important spark plug characteristics are the number of electrodes, heat rating and, in some cases, the ability not to interfere with radio reception.

Correct functioning of spark plugs is one of the most important conditions for efficient engine operation. It is necessary that only the prescribed type of spark plugs are installed on the engine. If the engine is in good condition, cleaning the spark plugs is a rare operation.

Tools needed to remove the spark plug and adjust the gap

Engine 1.6-I

Location of screws (1) for fastening the upper engine casing 1.6-I

Location of high-voltage wire tips (2) on spark plugs

1. Unscrew the screws and remove the upper engine casing, see Fig. Location of screws (1) for fastening the upper engine casing 1.6-I.

2. Mark the high-voltage wires with numbers and remove the high-voltage wire tips from the spark plugs, see Fig. "Location of the high-voltage wire tips (2) on the spark plugs".

3. Clean the spark plugs using a brush, vacuum cleaner or compressed air to prevent dirt from getting into the engine cylinders after the spark plugs are removed. Unscrew the spark plugs using a spark plug wrench.

Engine 1.8-I

Location of brackets (1) for fastening the upper engine casing 1.8-I

Location of high-voltage wire tips on spark plugs of 1.8-I engine

1. Release the two clamps and remove the upper engine casing, see Fig. Location of the clamps (1) for fastening the upper engine casing 1.8-I.


2. Mark the high-voltage wires with numbers and remove the high-voltage wire tips from the spark plugs, see Fig. Location of high-voltage wire tips on spark plugs of the 1.8-I engine.

3. Clean the spark plugs using a brush, vacuum cleaner or compressed air to prevent dirt from getting into the engine cylinders after the spark plugs are removed. Unscrew the spark plugs using a spark plug wrench.

Engines 2.3-I (5 cylinders)

Location of high-voltage wire tips on spark plugs of 2.3-I engine

1. Open the hood.

2. Mark the high-voltage wires with numbers and remove the high-voltage wire tips from the spark plugs, see Fig. Location of high-voltage wire tips on spark plugs of the 2.3-I engine.

3. Clean the spark plugs using a brush, vacuum cleaner or compressed air to prevent dirt from getting into the engine cylinders after the spark plugs are removed. Unscrew the spark plugs using a spark plug wrench.

Engines 2.8-I (6 cylinders)

Location of the screws for fastening the upper engine casing 2.8-I

1. Unscrew the screws and remove the upper engine casing, see Fig. Location of the screws securing the upper engine casing 2.8-I.

2. Mark the high-voltage wires with numbers and remove the high-voltage wire caps from the spark plugs.

3. Clean the spark plugs using a brush, vacuum cleaner or compressed air to prevent dirt from getting into the engine cylinders after the spark plugs are removed. Unscrew the spark plugs using a spark plug wrench.

All engines

Visual inspection of the working part of the spark plugs can show the condition of the engine. If the nose of the spark plug insulator is clean and white, without any deposits, this indicates that the mixture is too lean. This also indicates that the plug is too hot, i.e. the heat from the central electrode is slowly removed. If this is the case, it is necessary to adjust the fuel mixture or replace the plug.

If the nose of the insulator is covered with a black coating, this indicates that the mixture is too rich. If the coating is black and oily, this indicates engine wear and the need for inspection and repair. If the nose of the insulator is covered with a light brown coating, the mixture composition is optimal and the engine is in good condition.

The spark plug gap is very important because if the gap is too big or too small, the spark size changes, which leads to a decrease in engine efficiency. The gap must always meet technical requirements.

Measuring spark plug gap with a wire gauge

Measuring spark plug gap with feeler gauge

The gap is checked with a wire template or feeler gauge. The gap is adjusted by bending the side electrode. The central electrode should never be bent, as this can lead to breakage of the insulator and failure of the spark plug.

To bend the side electrode of the spark plug, you need to use a special tool.

Before installing the spark plug into the engine, check that the threads are clean and all threads are intact.

Screw in the spark plugs by hand and then tighten them to the specified torque.

Connect the high-voltage wires to the spark plugs.