Introduction

Today we’ll be changing the spark plugs on a W203 C200 Mercedes-Benz C-Class. Changing spark plugs in this vehicle is a very simple process, if not easier than an oil change.

Tools Required

  • Socket Set
  • E8 Torx Socket
  • Spark Plug Socket
  • Torque Wrench

Parts Required

  • x4 Replacement spark plugs (We used Denso IKH20TT)
  • Aluminium grade anti-sieze
  • Dielectric grease

Step 1

Remove the engine cover as pictured. Simply lift firmly upwards.

W203 C200 Changing Spark Plugs

Step 2

Here you can see the four spark plug coil packs we need to remove.

W203 C200 Changing Spark Plugs

Step 3

Each has two torx bolts holding the coil pack in place. Use an E8 socket to remove these.

W203 C200 Changing Spark Plugs

Step 4

As required you may need to unplug the coil pack or unplug neighbouring looms. Don’t forget to reconnect these later on.

W203 C200 Changing Spark Plugs
W203 C200 Changing Spark Plugs

Step 5

Lift up and remove the coil pack.

W203 C200 Changing Spark Plugs

Step 6

We will now remove the spark plugs. Push the spark plug socket firmly onto the spark plug to engage it. Using an extension bar and ratchet, remove the spark plug.

W203 C200 Changing Spark Plugs

Step 7

Here we have a comparison between the new and old spark plugs. The old spark plug travelled 60,000km.

W203 C200 Changing Spark Plugs

Step 8

It’s time to install the new spark plug. Apply even coverage of aluminium grade anti-seize and insert the spark plug into the engine. Engage the threads by hand to ensure they are not cross threaded.

W203 C200 Changing Spark Plugs

Step 9

Using a torque wrench, tighten the spark plug to 25nm.

W203 C200 Changing Spark Plugs

Step 10

Apply a small amount of dielectric grease into the coil pack and spread onto the metal terminal with a toothpick.

W203 C200 Changing Spark Plugs

Step 11

Reinstall the coil packs and hand tighten the bolts. You may feel some resistance when reinstalling, this is normal.

W203 C200 Changing Spark Plugs

Step 12

Repeat this process for all four spark plugs.

W203 C200 Changing Spark Plugs

Complete

Reconnect any looms you disconnected and reinstall the engine cover. Start the engine and listen for correct operation.

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