Index

Model

Chassis

Engine

Transmission

Mercedes-Benz

Replacing Spark Plug

Brand: Mercedes-Benz

Model: E350

Chassis: W212

​Engine: M276 DE35

Transmission: 722.9

Project: Maintenance

​Labor: 2 hours

E换火花塞(封面).jpg

Overview

Replacing spark plus is regular maintenance. There is a requirement every 60k miles or 6 years to replace the spark plugs in the MB maintenance booklet. To naturally aspirated engine of M276 DE35, there is a step to remove the resonance intake manifold to reach the ignition coil in the WIS. But that must replace a set of expensive intake plenum gaskets with more labor. Removing the ECU may make more room to reach the concealed ignition coil and spark plugs. More detail below.

Replace Spark Plugs of 4th, 5th & 6th Cylinder

Step 1  Open The Engine Hood

Substep:

1.1 Pull lever on left side of the footwell to unlock the engine hood. The engine hood jumps open; lift engine hood slightly if necessary;

1.2 Pull out handle and lift to open engine hood. (Windshield wiper arms must not be folded forward).

Step 2 Remove ECU (Important Step)

Substep:

2.1 Remove front engine cover;

2.2 Remove electric connecter from ECU;

2.3 Remove ECU;

2.4 Remove wire harness from resonance intake manifold;

2.5 Unscrew the bracket of electric wire harness.

Step 3 Remove the Used Spark Plug of 6th Cylinder (The Most difficult One)

Substep:

3.1 Detach connector of ignition coil;

3.2 Remove bolt of ignition coil;

3.3 Pull ignition coil upwards and remove;

3.4 Remove spark plug.

Step 4 Install the New Spark Plus of 6th Cylinder

Substep:

4.1 Install new spark plug with 23Nm (204 Ib-in);​

4.2 Apply dielectric grease on the lip of spark plug connector;

4.3 Install ignition coil with 9Nm (80 Ib-in) on bolts;

4.4 Install connector to ignition coil with dielectric grease;

4.5 Connect the wire harness to intake manifold.

Step 5 Replace the Spark Plug of 4th, 5th Cylinder

Substep:

5.1 Replace spark plugs of 4th, 5th cylinder same with step 3-4;

5.2 Install ECU with the reverse of step 2.

Replace the Spark Plugs of 1st, 2nd & 3rd Cylinder

Step 6 Remove Air Filter Housing

Substep:

6.1 Detach the connector of the airflow sensor;

6.2 Unscrew two bolts for air filter housing;

6.3 Loosen the clamp for intake hose;

6.4 Remove air filter housing.

Step 7 Replace the Spark Plugs of 1st, 2nd & 3rd Cylinder, Finish the work