Information On Avoiding Damage When Replacing Spark Plugs - AH15.10-P-0002-02A

WARNING: This page is about a different car, the 2023 Mercedes-Benz GLC300, 2022 Mercedes-Benz GLC300, 2021 Mercedes-Benz GLC300, 2020 Mercedes-Benz GLC350e, and 2020 Mercedes-Benz GLC300. However, it is still accessible from the selected car via links, so may be relevant.

Model all (4xWD, CAR, smart)

General

Before starting work, switch the ignition to position "0".
The ignition system should only be operated if all components of the ignition system are completely installed, tightened to the specified torque and connected.

Cleaning

Before the spark plugs are removed, dirt residue must be blown out of the spark plug wells using compressed air.
Take care when cleaning with compressed air in the area of the hot wire and hot film mass air flow sensor!

It must be ensured that no compressed air is blown into the hot wire and hot film mass air flow sensor.

The hot wire and hot film mass air flow sensor can otherwise be damaged.

Openings through which contamination or foreign objects can be brought into the Engine, its ancillaries or its detachable parts must be sealed off using suitable caps, stop plugs or clean, lint-free rags before cleaning is started.

The spark plug wells adjacent to the spark plug well that is to be blown out with compressed air must also be covered.

Damage can occur otherwise.
With AMG Engines 133, 139, 176, 177 and 178, the spark plug wells also need to be vacuumed out after the spark plugs are removed.

There must not be any dirt particles in the spark plug wells and on the sealing surface of the spark plugs in the cylinder head!

Damage can occur otherwise.

Check

All ignition system components which are worked on during the spark plug change must be visually inspected for damage. If problems are found, they must be removed subject to a separate repair order.

Installation

Before installation, the rubber lips of the spark plug connectors must be greased using spark plug connector grease.

The rubber lips of the spark plug connectors must be greased! The spark plug connectors can otherwise be damaged the next time they are removed.