MAINTENANCE
2015 Ford Explorer Spark Plugs & Replacement
When to replace 2015 Explorer spark plugs, how to spot ignition problems, and why the correct plugs depend on the engine.
Confirm the vehicle's engine, trim, drivetrain, market and equipment. The exact procedure may differ, even within the same model year.
2015 Ford Explorer reference
| Item | Ford guidance |
|---|---|
| Normal scheduled plug replacement | 100,000 mi / 160,000 km |
| Engine coverage | 3.5L V6, 2.0L EcoBoost, 3.5L EcoBoost: verify engine-specific plug fitment |
| Common related codes | P0300–P0306 (depending on engine) |
Spark plug specifications, gap and torque must be checked for the exact engine and plug; they are not assumed here.
Replacement interval
Ford lists spark plug replacement at 100,000 miles (160,000 km) in the normal 2015 Explorer maintenance schedule. The interval is a service target, not a guarantee that plugs will remain healthy until that mileage. Hard starts, hesitation or misfire codes justify inspection sooner. Towing and other unusual conditions can change maintenance needs; refer to the special operating conditions schedule.
Which engine do you have?
The 2015 Explorer could be equipped with a 3.5L naturally aspirated V6, a turbocharged 2.0L EcoBoost four-cylinder or a twin-turbocharged 3.5L EcoBoost V6. Plug part numbers and access procedures are not interchangeable across those engines. Confirm the VIN and engine identification before ordering parts. The featured XLT on this site has the naturally aspirated 3.5L V6.
Symptoms of worn plugs
Rough idle, a shudder under acceleration, reduced fuel economy, hesitant starts and P0300-series misfire codes can point toward ignition trouble. They can also come from an ignition coil, injector, air leak, mechanical condition or fuel supply issue. Read stored codes and note when the symptoms appear before concluding that plugs are responsible.
What makes replacement challenging
On transverse V6 engines, some plugs may be less accessible than others. Hot components, wiring connectors and brittle coil boots introduce risks if the job is rushed. A controlled process includes allowing the engine to cool, cleaning around the plug wells, carefully removing coils and checking for oil or moisture before removing plugs.
Gap and tightening
Do not guess a universal gap or tightening torque from another Ford engine. Read the service specification for the exact engine and replacement plug. Incorrect torque can damage cylinder-head threads; excessive gap or damaged electrodes can lead to repeat misfires. Avoid forcing a plug that does not thread smoothly by hand.
Coils and misfire diagnosis
A single-cylinder misfire may respond to carefully comparing coil, plug and injector evidence; a multiple-cylinder misfire needs a broader assessment. A professional scan tool can display live and stored misfire information. Replace only verified faulty parts, not an entire bank of coils automatically.
After servicing
Check that each connector is securely latched and each coil boot is fully seated. Confirm normal idle and acceleration, and inspect for newly set trouble codes. Keep a record of the date, distance and plug part number so the next owner knows exactly what was installed.
Before ordering replacement plugs
Identify the engine and use the Ford-specified part or equivalent with the correct fit, heat range and gap requirements. Turbocharged EcoBoost applications should not automatically use parts selected for the naturally aspirated V6. The 100,000-mile normal-service interval is a planning reference; a misfire may require earlier inspection.
Avoid damaging the cylinder head
Work on a suitably cooled engine and prevent grit from falling into a plug well. Use the proper socket and torque procedure rather than overtightening. If access requires removing intake parts or ignition components you cannot safely reinstall, a trained technician is the better option.
What to inspect when plugs are removed
Retain the old plugs in cylinder order if a misfire is under investigation. Their appearance can offer clues about oil contamination, fuel mixture or overheating, but appearance alone is not a definitive diagnosis. Inspect the plug wells for oil or moisture and the coil boots for tracking or damage. Use parts confirmed for the engine by VIN; a plug that physically threads in is not necessarily correct for heat range or electrode design. Follow Ford torque and installation procedures and avoid cross-threading the aluminium cylinder head.
Use the correct model-year manual and current service information. Stop if instructions or safety precautions are unclear, and use a qualified technician for work you cannot verify.
References and further reading
This independent guide is not endorsed by the vehicle manufacturer. Let us know if you spot an error.