2019 Mercedes-Benz Sprinter Spark Plug Guide

Quick Reference: 2019 Sprinter Spark Plugs

Note: Diesel engines like the 3.0L OM642 V6 use glow plugs for combustion aid, not spark plugs.

Why the Right Spark Plug Matters

Using the correct spark plug is critical for engine performance, fuel economy, and longevity. The engineers at Mercedes-Benz selected a very specific plug for the 2.0L gasoline engine, and deviating from this specification can cause issues. Key factors include:

• Heat Range: This determines how quickly the plug dissipates heat from the combustion chamber. A plug that is too "hot" (dissipates heat too slowly) can lead to pre-ignition (detonation), which can cause catastrophic engine damage. A plug that is too "cold" can accumulate carbon deposits, leading to misfires.
• Electrode Material: The M274 engine comes from the factory with Iridium-tipped spark plugs. These are a premium, long-life material designed for the high-energy demands of modern ignition systems.
  • Iridium/Platinum: These precious metals have extremely high melting points and offer superior resistance to wear. This allows them to maintain a precise, sharp electrode edge for a consistent spark over a very long service life (typically 60,000–100,000 miles).
  • Copper: While excellent conductors, standard copper plugs have a much shorter lifespan (typically 20,000–30,000 miles) and are not specified for this engine. Using them would result in rapid performance degradation and potential misfires.

How to Gap a Spark Plug

Properly gapping a spark plug ensures the spark has the perfect distance to jump, creating the most effective flame kernel to ignite the air-fuel mixture. For the 2019 Sprinter's 2.0L gas engine, the specified gap is 0.028 inches (0.7mm).

Modern Iridium plugs are often pre-gapped from the factory. However, it's crucial to verify this gap before installation, as they can be mishandled during shipping. Never use a "coin-style" gapper on Iridium or Platinum plugs. The fine-wire electrodes are fragile and can be easily damaged or broken.

1. Use a Feeler Gauge or Wire-Loop Tool: Select the 0.028" blade or wire on your gauge.
2. Check the Gap: Gently slide the gauge between the center and ground electrodes. It should pass through with a slight drag. If it's too loose or won't fit, the gap needs adjustment.
3. Adjust Carefully: To adjust, use the tool on your gapper to gently bend only the ground strap (the outer L-shaped electrode). Never pry against or put pressure on the fragile center electrode. Make tiny adjustments and re-check until the gap is perfect.

Replacement Procedure Tips for the M274 Engine

Replacing the spark plugs on the 2.0L Sprinter engine is straightforward for an experienced DIYer. The engine uses a modern coil-on-plug ignition system, meaning each spark plug has its own individual ignition coil sitting directly on top of it. There is no distributor or old-fashioned spark plug wires.

1. Coil-on-Plug Removal: After removing the engine cover, you will see the four ignition coils. Disconnect the electrical connector from each coil. Then, unbolt the single hold-down bolt (typically an E-Torx or standard hex head). The coil can then be gently twisted and pulled straight up to remove it.
2. The Anti-Seize Debate: This is a hotly debated topic. Most modern spark plug manufacturers (including NGK) apply a special trivalent (zinc-chromate) plating to their plug threads that acts as an anti-corrosive and anti-seize agent. They do not recommend applying additional anti-seize compound. Applying it can alter the torque reading, causing you to over-tighten the plug, which can stretch the threads in the aluminum cylinder head or damage the plug. Our recommendation is to follow the plug manufacturer's guidelines and install them clean and dry.
3. Dielectric Grease: A small amount of dielectric grease applied to the inside of the spark plug boot (the end of the ignition coil that fits over the plug) is highly recommended. This grease does not conduct electricity; instead, it seals the boot, prevents voltage leaks, and keeps moisture out. It also makes future coil removal much easier.
4. Torque Correctly: Use a torque wrench. The specified torque for the M274 engine is 17 lb-ft (23 Nm). Over-tightening can damage the cylinder head, while under-tightening can allow the plug to back out or cause poor heat transfer.

Known Issues

For this specific 2019 Sprinter platform, there are no widely recognized, systemic issues related to spark plug failure like the infamous Ford 3-valve Triton plug breakage or problems with specific GM ionization-sensing coils. The Mercedes M274 engine and its ignition components are generally considered robust and reliable when serviced with OEM-quality parts at the correct intervals.

Need plugs replaced? Find a shop on Repairius.