Complete major tune-up service including spark plug replacement, ignition coil inspection, air filter replacement, fuel filter service, throttle body cleaning, PCV valve service, and engine oil change with comprehensive system inspection.

Warnings

Tools required

Parts

• Spark plugs - 3.5L EcoBoost (set of 6) × 6 — Motorcraft SP-546 or equivalent
• Engine air filter × 1 — Motorcraft FA-1927 or equivalent
• Engine oil filter × 1 — Motorcraft FL-400-S or equivalent
• Oil drain plug crush washer × 1 — Use OEM specification
• PCV valve × 1 — Use OEM specification
• Cabin air filter (recommended) × 1 — Motorcraft FP-79 or equivalent

Fluids

• Motorcraft 0W-20 Full Synthetic — 6 qt

Preparation

1. Park vehicle on level surface, engage parking brake, and allow engine to cool completely (minimum 2 hours)
2. Gather all tools, parts, and fluids before beginning work
3. Disconnect negative battery terminal and wait 5 minutes for system capacitors to discharge
4. If accessing components from below, safely raise and support vehicle on jack stands at manufacturer-specified lift points
5. Remove engine cover by pulling upward on cover clips (no fasteners on most models)
6. Place drain pan, tools, and parts within easy reach of work area

Procedure

1. 1

   Replace engine air filter
   Locate air filter housing on driver side of engine bay. Release clips on air box lid (typically 4 clips). Open housing and remove old air filter. Inspect housing for debris and clean if necessary. Install new air filter ensuring proper seating and directional arrows point toward engine. Close lid and secure all clips.
   Torque spec

   Air Box Clips5 Nm (4 lb-ft)
2. 2

   Access and inspect ignition coils
   Locate ignition coil-on-plug assemblies on both cylinder banks. On 3.5L EcoBoost, coils are positioned on the outer sides of engine. Remove any wiring harness clips or brackets preventing access to coils. Disconnect electrical connectors from each of the 6 ignition coils by pressing release tabs and pulling straight up. Remove mounting bolts from each coil using appropriate socket.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
3. 3

   Remove ignition coils and access spark plugs
   Carefully pull each ignition coil straight up and out of spark plug wells. Inspect coil boots for tears, cracks, or carbon tracking. Inspect coil towers for corrosion. If coils show damage or vehicle has ignition-related codes, replace as needed. Set coils aside in order to maintain cylinder position tracking. Check spark plug wells for oil or debris accumulation - if oil is present, investigate valve cover gasket condition.
   ⚠Oil in spark plug wells indicates valve cover gasket leakage and should be addressed to prevent coil failure.
4. 4

   Remove old spark plugs
   Using compressed air or a clean cloth, remove any debris from around spark plug wells to prevent contamination. Install spark plug socket onto first plug and carefully loosen counterclockwise. Remove spark plug completely. Inspect plug electrode condition, gap, and insulator color for engine health indicators. Repeat for all 6 cylinders. Compare plug condition across cylinders - significant variation may indicate cylinder-specific issues.
   ℹ️3.5L EcoBoost uses specific heat-range plugs due to turbocharging. Do not substitute with non-approved alternatives.
5. 5

   Install new spark plugs
   Verify new spark plugs are correct part number for 3.5L EcoBoost. Check factory gap specification (typically 0.030-0.032 inches, but verify). Apply small amount of anti-seize to plug threads (optional but recommended for aluminum heads). Hand-thread each plug into cylinder head, being extremely careful not to cross-thread. Once finger-tight, torque plugs to manufacturer specification (typically 11-13 ft-lbs for this engine - follow plug manufacturer instructions if provided with plugs).
   ⚠Cross-threading spark plugs in aluminum heads can cause catastrophic damage requiring head replacement. Always start plugs by hand.
6. 6

   Reinstall ignition coils
   Apply thin coating of dielectric grease to inside of each coil boot to prevent moisture intrusion and aid future removal. Carefully align each coil over its corresponding spark plug and press down firmly until fully seated. Install mounting bolts and torque to specification. Reconnect electrical connectors to each coil, ensuring positive click engagement. Verify all connectors are fully locked.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
7. 7

   Service PCV valve and system
   Locate PCV valve on passenger side valve cover (typically integrated into valve cover or connected via hose). Disconnect vacuum hose from PCV valve. Remove PCV valve by rotating counterclockwise or releasing retaining clips depending on design. Shake old valve - it should rattle indicating free movement. Install new PCV valve, ensuring proper seating and orientation. Reconnect vacuum hose securely. Inspect all PCV system hoses for cracks or deterioration and replace if necessary.
   ℹ️A stuck PCV valve can cause increased crankcase pressure leading to oil leaks and poor idle quality.
8. 8

   Clean throttle body
   Locate throttle body on intake system. Disconnect air intake tube from throttle body by loosening clamp. Using throttle body cleaner and clean cloth, carefully clean throttle plate and bore. Do not force throttle plate open with excessive pressure. Spray cleaner and allow to soak briefly, then wipe clean. Avoid getting cleaner on throttle position sensor. Clean both sides of throttle plate. Reconnect air intake tube and secure clamp.
   ⚠Do not use carburetor cleaner on throttle bodies with electronic components. Use only throttle body-specific cleaner.
9. 9

   Drain engine oil
   Locate oil drain plug on bottom of oil pan (access from underneath vehicle). Position drain pan directly beneath drain plug. Using appropriate socket, carefully loosen drain plug. Allow plug to unthread until nearly loose, then quickly remove while pulling away to avoid oil stream. Allow engine to drain completely (10-15 minutes). Inspect drain plug and threads for damage. Remove old crush washer from drain plug and install new washer.
   ⚠Even after cooling period, engine oil may still be warm. Wear appropriate gloves to protect from hot oil.
10. 10

    Replace oil filter
    Locate oil filter on driver side of engine block (accessed from below). Position drain pan beneath filter. Using oil filter wrench, rotate filter counterclockwise to remove. Expect oil spillage. Once removed, inspect filter mounting surface on engine block and clean with shop towel. Apply thin film of clean engine oil to rubber gasket on new oil filter. Hand-thread new filter onto mounting boss, turning clockwise. Once gasket contacts mounting surface, tighten an additional 3/4 to 1 full turn by hand only - do not use wrench.
    ℹ️Over-tightening oil filters can damage gasket and cause leaks. Hand-tight plus 3/4 turn is sufficient.
11. 11

    Install drain plug and refill engine oil
    Clean drain plug threads and oil pan surface. Install drain plug with new crush washer and torque to specification. Remove oil fill cap on driver side valve cover. Using funnel, add 5.5 quarts of Motorcraft 0W-20 synthetic oil initially. Wait 2 minutes for oil to drain into pan. Check oil level with dipstick. Add remaining oil in small increments until level reaches full mark on dipstick. Install oil fill cap securely.
    Torque spec

    Oil Drain Plug35 Nm (26 lb-ft)
12. 12

    Replace cabin air filter (recommended)
    Open glove box and remove contents. Press inward on both sides of glove box to release stops and lower completely. Locate cabin air filter housing behind glove box. Press release tabs and remove filter cover. Slide out old cabin air filter noting airflow direction arrow. Insert new filter with arrow pointing toward rear of vehicle (same direction as old filter). Replace cover ensuring tabs lock securely. Reinstall glove box stops.
    ℹ️While not strictly part of engine tune-up, cabin air filter replacement is recommended during major service intervals.
13. 13

    Inspect belts and hoses
    Visually inspect serpentine belt for cracks, glazing, fraying, or missing ribs. Check belt tensioner for proper operation and any fluid leakage from tensioner bearing. Inspect all coolant hoses for soft spots, cracks, or bulging. Check turbocharger inlet/outlet hoses for secure connections and any signs of oil leakage. Inspect intercooler hoses and clamps for tightness. Document any components requiring future replacement.
    ℹ️3.5L EcoBoost turbo system operates under high pressure. Loose intercooler connections can cause significant performance loss and turbo damage.

Reassembly

1. Reinstall engine cover by aligning mounting points and pressing down until clips engage
2. Reconnect negative battery terminal and tighten securely
3. If vehicle was raised, carefully lower from jack stands and remove safety equipment
4. Double-check that all tools have been removed from engine bay
5. Verify oil fill cap, air filter housing, and all other access panels are properly secured

Verification

• Start engine and allow to idle. Monitor for unusual noises, vibrations, or warning lights
• Check oil pressure gauge or warning light to confirm proper oil circulation within 5 seconds of startup
• Inspect underneath vehicle for any oil leaks from drain plug or filter after 1-2 minutes of running
• Verify smooth idle with no misfires. Engine should settle to smooth idle within 30 seconds
• Rev engine gently to 2000-3000 RPM and verify smooth acceleration with no hesitation
• Check for any visible smoke from exhaust (white, blue, or black) indicating potential issues
• Allow engine to reach operating temperature and verify cooling system operation
• Turn off engine and recheck oil level after 5-minute settling period. Top off if needed
• Clear any diagnostic trouble codes that may have set during battery disconnection using OBD-II scanner if available
• Test drive vehicle for 10-15 minutes, monitoring engine performance, boost operation, and temperature
• After test drive, perform final inspection for leaks, verify proper oil level, and check for any new warning lights

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