Quick answer: Spark Plug Replacement on a 2019–2022 Mercedes-Benz A-Class is rated Advanced and takes about 1-3 hours. You'll need 4 tools for this job, and parts cost about $115. This guide walks you through the full job step by step, including the mistakes to avoid.
| Part Name |
Part Number |
Price |
Buy |
| Correct spark plug set for the gasoline/ICE engine in 2019-2022 Mercedes-Benz A-Class; verify engine, heat range, gap, and VIN fitment |
— |
$115.00 |
|
| Coil-boot seals or ignition coils only if inspection finds damage Optional |
— |
$35.00 |
|
About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.
💡 Pro tip: Order all parts at once to save on shipping
Step-by-Step Instructions
Follow these steps carefully
1
Confirm engine and plug fitment
Confirm your 2019-2022 Mercedes-Benz A-Class (W177): in North America this is the A220 with the 2.0L turbocharged M260 four-cylinder. It takes four iridium spark plugs — the commonly listed fitment is the NGK 93501 Iridium IX — gapped to the spec on your underhood emissions label (confirm the exact part number against your owner's manual or a Mercedes parts counter before ordering, as plug revisions exist for the M260). These are long-life iridium plugs on roughly a 60,000-mile interval. Scan for misfire codes (P0300-P0304) first; on the M260 a single-cylinder miss under boost is often the plug or its coil.
2
Cool and expose the plugs
Remove the large plastic engine cover, which pulls up off its grommets to expose the four coil-on-plug units in a row along the top of the valve cover. Disconnect the negative battery terminal.
3
Remove the ignition coils
Press the release tab on each coil connector and unplug it, remove the coil hold-down bolts, and pull each coil straight up with a gentle twist to break the boot seal. Keep the four coils in order on a clean rag.
4
Remove and install plugs
Loosen each old plug with a 16mm (5/8-inch) thin-wall spark plug socket and a 6-inch extension, keeping the socket straight in the deep wells, and compare each new plug to the old one: identical thread, reach and heat range. Verify the factory gap with a wire gauge against your emissions label spec — never pry on the fine iridium tip; discard any plug that arrives out of spec. Thread each plug in by hand for several full turns until the gasket seats, then torque to the spec in your owner's manual. Install them dry: modern coated plug threads need no anti-seize, which would corrupt the torque reading.
5
Reconnect and verify
Apply a thin film of dielectric grease inside each coil boot only — rubber, never the plug — to seal out moisture and ease the next removal. Push each coil firmly onto its plug, torque the hold-down bolts snug, and reconnect every locking-tab connector with a click. Refit the intake ducting, engine cover and battery terminal exactly as they were. Start the 2019-2022 Mercedes-Benz A-Class and confirm a smooth idle with no check-engine light. Road-test including some boost, then rescan for codes; a misfire that returns on one cylinder points to that cylinder's coil pack, not the new plugs.
🔧 Mechanic's note — Tom Becker
Dielectric grease goes inside the coil boot only — never on the plug. I've seen grease migrate and cause misfires.
All Done!
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
- • Using the wrong plug or assuming a pre-gapped plug needs no verification
- • Blowing debris into an open cylinder or plug well
- • Cross-threading a plug or tightening it without a torque wrench
- • Overusing anti-seize or dielectric grease on the plug threads
- • Mixing coil connectors or ignoring a misfire after reassembly
