2020 Mercedes-Benz Metris Spark Plug Type & Gap

<h2>Quick reference</h2>

Engine	OEM Plug PN	Aftermarket (NGK/Denso/Motorcraft)	Gap (in/mm)	Torque (lb-ft / Nm)	Interval
2.0L M274 I4 Turbo	Mercedes-Benz A 004 159 64 03	NGK PLKER7A8EGS	0.032 in / 0.8 mm	17 lb-ft / 23 Nm	60,000 miles (100,000 km)

<h2>Why the right plug matters</h2>

Choosing the correct spark plug for your 2020 Mercedes-Benz Metris is crucial for optimal engine performance, fuel efficiency, and to prevent costly damage. Spark plugs are not a universal component; they are meticulously designed for specific engines, considering factors like heat range, electrode material, and gap.

• Heat Range: This refers to the plug's ability to dissipate heat. A plug that's too "cold" can lead to carbon fouling, while a plug that's too "hot" can cause pre-ignition and engine damage. The specified OEM plug has the precise heat range for your Metris's 2.0L M274 engine, ensuring efficient combustion and preventing issues.

• Electrode Material:

  • Iridium: The most common choice for modern vehicles, including your Metris. Iridium plugs offer exceptional durability and a very fine electrode tip for a strong, consistent spark. This translates to longer service intervals and improved combustion efficiency.
  • Platinum: While not typically found in the Metris, platinum plugs offer good durability and a longer lifespan than copper, but not as long as iridium.
  • Copper: Historically used, copper plugs conduct electricity very well but have a shorter lifespan due to the softer electrode material. They are generally not recommended for modern engines designed for iridium or platinum.

The 2020 Metris 2.0L M274 engine is designed for long-life iridium spark plugs. Using an inferior material can lead to misfires, reduced fuel economy, and premature wear, requiring more frequent replacements.

<h2>How to gap a spark plug</h2>

While many modern iridium spark plugs come pre-gapped, it's always a good practice to verify the gap before installation. Incorrect gapping can lead to misfires, rough idling, and decreased fuel efficiency.

To check and adjust the spark plug gap:

1. Use a wire gauge tool: A wire-type spark plug gapping tool is ideal for iridium plugs as it minimizes the risk of damaging the delicate iridium tip. Avoid using disc-style gapping tools, as they can inadvertently bend or break the fine electrode.
2. Measure the gap: Slide the appropriate wire gauge through the gap between the center and ground electrodes. There should be a slight drag.
3. Adjust if necessary: If the gap is too small, carefully use the gapping tool's adjuster to lightly bend the ground electrode outward. If the gap is too wide, gently tap the ground electrode on a clean, hard surface to close it. Always make small adjustments to avoid over-bending.

For your 2020 Mercedes-Benz Metris 2.0L M274 engine, the recommended gap is 0.032 inches (0.8 mm).

<h2>Replacement procedure tips</h2>

The 2020 Mercedes-Benz Metris 2.0L M274 engine utilizes a coil-on-plug ignition system, meaning each spark plug has its own individual ignition coil directly mounted on top of it. This design improves spark delivery and eliminates the need for spark plug wires.

Here are some tips for a smooth replacement:

• Cool Engine: Always allow the engine to cool completely before attempting to remove spark plugs. Removing plugs from a hot engine can increase the risk of thread damage to the cylinder head.
• Coil-on-Plug Removal: Carefully disconnect the electrical connector from each ignition coil, then gently pull upwards on the coil to remove it. Avoid prying against other engine components.
• Clean the Area: Before removing the old plugs, use compressed air to blow out any debris around the spark plug wells. This prevents dirt and grime from falling into the combustion chamber once the old plug is removed.
• Anti-Seize Debate: There is ongoing debate about using anti-seize on spark plug threads. For modern spark plugs with nickel-plated shells, manufacturers like NGK generally advise against using anti-seize. The nickel plating provides adequate anti-seize properties, and adding more can alter the torque readings, potentially leading to over-tightening and damage. Follow the spark plug manufacturer's recommendations.
• Dielectric Grease: Apply a small amount of dielectric grease inside the rubber boot of each ignition coil before reinstallation. This helps to seal out moisture, prevents corrosion, and makes future removal easier.
• Torque Wrench is Essential: Always tighten spark plugs to the manufacturer's specified torque using a reliable torque wrench. Over-tightening can strip cylinder head threads or crack the spark plug insulator, while under-tightening can lead to combustion gas leaks and overheating. For your Metris, the torque spec is 17 lb-ft / 23 Nm.

<h2>Known issues</h2>

Fortunately, there are no widespread or notorious known issues specifically related to spark plugs or their removal/installation for the 2020 Mercedes-Benz Metris 2.0L M274 engine, unlike some other vehicle platforms (e.g., Ford 3-valve engines with two-piece plugs).

Focus on using the correct OEM-specified iridium plugs, properly gapping them (if necessary), and adhering to the recommended torque specifications for a trouble-free spark plug service.

Need plugs replaced? Find a shop on Repairius.