How to replace the spark plugs on Mitsubishi Lancer EX 2.0 16V (MIVEC, 4B11 engine)

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  • OVERALL DIFFICULTY INDEX: 3/10
  • IF YOU HAVE NO TOOLS, YOU SPEND $20 TO GET THEM FOR THIS JOB
  • IF YOU HAVE NO EXPERIENCE YOU SPEND 1 HOUR TO CARRY OUT THIS JOB
  • RISK OF BURNS, SEE BELOW​
BEFORE YOU START
  • Be careful not to touch any hot part of the engine.​
  • Better to replace the spark plugs on a warm or cold engine
DISCLAIMER:
Our pictorials are of informative nature and do illustrate works carried out by ourselves at our own premises for our own use and satisfaction.
Readers who envisage to carry out similar works inspired by the below method shall do this at their own risks and liability.
NOTE: this tutorial is valid for the following Mitsubishi, Peugeot and Citroën models, all equipped with the same Mitsubishi MIVEC 4B11 engine:
  • Mitsubishi Lancer
  • Mitsubishi ASX (depending on model-year)
  • Mitsubishi Outlander
  • Mitsubishi Outlander Sport (depending on model-year)
  • Peugeot 4007 and 4008
  • Citroën C-Crosser and C4 Aircross

When and why to replace the spark plugs - Symptoms of worn spark plugs

The frequency at which you should change your spark plugs is as follows:
  • Every 60,000 Km in normal driving conditions
  • Every 20,000 Km and sometimes less, in severe driving conditions including bad gasoline quality, engine with high oil consumption, daily upwards driving on steep slopes.
Not replacing the spark plugs leads to the following engine deterioration / symptoms:
  • Carbon build-up inside the combustion chamber
  • Excessive fuel consumption
  • Possible black smoke seen from exhaust
  • Engine hesitation or misfires upon accelerating at low and medium speed

How to replace the spark plugs on the Mitsubishi Lancer 2.0 EX

Unscrew and remove the coils' cover under the shown red arrows
Unscrew and remove the COPs (Coil-On-Plug)
Unscrew and remove the spark plugs while keeping them in the same order than the cylinders for later performing an engine diagnostic per cylinder:

Checking the COPs and Spark Plugs condition

Inspect well the COPs for the below failures:
  • Cracks or traces of burns on the insulator
  • Cracked rubber (boot)
  • Presence of the spring that connects to the plug
  • Integrity of the seal, where it plugs the spark plug well and seals it.
Inspect well the spark plugs one by one, while making sure of the concerned cylinder for the following:
  • Color of electrodes
  • Condition of electrodes and how worn they are
  • Burns on the insulator
  • Presence of oil or water on the electrodes
Check our full guide on how to determine the engine condition out of the spark plugs appearance by clicking on the below link for the dedicated page.

Refitting new spark plugs and the COPs to the Mitsubishi 4B11 engine

Like for any engine, do not drop the spark plugs into their wells, rather place them with a magnet tool or dedicated socket equipped with a rubber plug holder.
Tighten by hand first, then to a torque of 2.5 mKg.
Clean well the COPs with a dry shop towel, you may use an electronic cleaner spray.
If you were facing misfires from time to time in a particular cylinder, insulate the COPs with a dielectric silicone, check our below link for details.
Clean well the plastics around the COPs from dust, mud, water, etc. prior to refitting the cover.

See also our other tutorials on Japanese cars and all cars...

...and buy your spark plugs from our partners' stores, please make sure of compatibility with your engine!