2015–2020 BMW M4

2015-2020 BMW M4 — Spark Plug and Ignition Coil Replacement

By Ray Delgado ✓ Certified Mechanic · Published Sep 24, 2026 · Updated Oct 14, 2026

🔧🔧🔧 Advanced 3–4 hours $313 DIY

Save $31 by doing it yourself! Shop cost: $344

Quick answer: Spark Plug and Ignition Coil Replacement on a 2015–2020 BMW M4 is rated Advanced and takes about 3–4 hours. You'll need 8 tools for this job, and parts cost about $313. This guide walks you through the full job step by step, including the mistakes to avoid.

Quick Video Tutorial

Parts You Need

Total Cost

$313.00

Part Name	Part Number	Price	Buy
Spark plugs, S55-specific (6)	—	$130.00	Amazon
Ignition coils (6, if replacing)	—	$177.00	Amazon
Dielectric grease	—	$6.00	Amazon

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

Confirm the S55 engine and gather parts

Covers the F82 M4 (also F80 M3/F87 M2) with the S55 twin-turbo inline-six, 2015-2020. Order six S55-specified plugs, plus new coils if replacing as a set. No generic plugs — the S55's high boost needs correct heat range and gap.

Let the engine cool and disconnect the battery

Work on a completely cold engine — removing plugs from a hot aluminum head risks thread damage. Disconnect the negative battery terminal so no coil can fire near the plug wells. Wait at least 30 minutes after driving before starting.

Remove the engine covers and intake ducting

Remove the plastic engine cover and the intake ducting blocking the coil packs on the S55 valve cover. Label every electrical connector and vacuum line you disconnect with tape so nothing is misrouted on reassembly.

Unplug and remove the ignition coils

Release each locking tab and pull the coil up out of the plug well. Work one cylinder at a time, keeping the coils in order so each returns to its original cylinder. Inspect the boots for cracks or carbon tracking.

Blow out the plug wells and remove the old plugs

Blast each plug well with air before loosening. Remove each plug with a socket and extension, turning to avoid snapping a seized plug. Compare color across all six — oil fouling points to a valve cover gasket issue.

🔧 Mechanic's note — Ray Delgado

I read those old plugs like a report card — I compare all six side by side, and I've learned one oil-fouled plug is an early warning of a valve cover gasket leak, and catching it now saves me doing this job twice.

Gap and install the new spark plugs

Verify each new plug's gap against the S55 spec. Thread each plug in by hand for several turns to avoid cross-threading, then torque to the specified value — overtightening in an aluminum head is a costly mistake.

🔧 Mechanic's note — Ray Delgado

I use the torque wrench on these — the S55's aluminum head doesn't forgive overtightened plugs, and I've seen a stripped plug thread turn a Saturday job into a machine-shop bill.

Reinstall the coils and reconnect everything

Push each coil firmly back onto its plug until it seats, then reconnect the electrical connectors until the locks click. Reinstall the intake ducting and engine covers in reverse order, double-checking every labeled connector. Reconnect the negative battery terminal last.

Start the engine and verify

Start the engine and listen for a smooth, even idle with no misfire shake. Take a varied drive including light boost, and confirm no check-engine light. If a misfire code returns on one cylinder, recheck that coil's connector seating first.

All Done!

Test your repair before closing everything up. If something doesn't work right, double-check your steps.

⚠️ Common Mistakes to Avoid

• Cross-threading a plug by starting it with a ratchet instead of by hand.
• Installing plugs with the wrong gap, causing misfires under boost.
• Mixing up coil order or leaving a connector unlocked.
• Dropping debris into an open plug well by skipping the compressed-air blowout.

Tools You'll Need

Socket set Spark plug socket Torque wrench Extensions Compressed air Screwdrivers Trim tools Masking tape and marker

⚠️ Safety First!

• Work only on a cold engine to avoid burns and thread damage in the aluminum head.
• Disconnect the battery before handling ignition components.
• Wear eye protection when blowing debris out of plug wells with compressed air.