Replace the front crankshaft main seal on the 2021-2024 Ford F-150 3.5L EcoBoost engine by removing the crankshaft pulley and timing cover to access the seal.

Warnings

Tools required

Parts

• Front crankshaft seal × 1 — Use OEM Ford specification
• Timing cover gasket × 1 — Use OEM Ford specification
• Oil pan gasket/sealant (front section) × 1 — Motorcraft RTV or OEM
• Oil drain plug crush washer × 1 — Use OEM specification
• Engine oil and filter × 1 — 0W-20 Full Synthetic
• Engine coolant × 1 — Motorcraft Orange Coolant premix

Fluids

• Motorcraft 0W-20 Full Synthetic — 6 qt
• Motorcraft Orange Coolant — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable and secure away from terminal
3. Remove engine cover by lifting upward from mounting grommets
4. Raise and safely support front of vehicle on jack stands
5. Remove lower engine splash shield fasteners and remove shield
6. Place drain pan under engine and remove oil drain plug, drain engine oil completely
7. Remove oil filter to ensure complete drainage
8. Partially drain coolant by opening radiator petcock or removing lower hose until level drops below timing cover
9. Allow adequate time for fluids to drain completely (15-20 minutes)

Procedure

1. 1

   Remove serpentine belt and tensioner
   Rotate serpentine belt tensioner clockwise using a 3/8 inch breaker bar in the square hole on tensioner. Remove belt from all pulleys and note routing diagram on radiator shroud or take photo. Remove tensioner mounting bolts and remove tensioner assembly from engine.
   Torque spec

   Mounting Bolts54 Nm (40 lb-ft)
2. 2

   Disconnect electrical connectors and sensors
   Disconnect the crankshaft position sensor electrical connector located near the timing cover. Remove sensor mounting bolt and carefully extract sensor from timing cover. Disconnect camshaft position sensor connectors at the top of the timing cover. Label all connectors for proper reassembly.
   Torque spec

   Mounting Bolts54 Nm (40 lb-ft)

   Electrical Connector Bolts8 Nm (6 lb-ft)
3. 3

   Remove crankshaft pulley/harmonic balancer
   Use a pulley holding tool or strap wrench to prevent crankshaft rotation. Remove the crankshaft pulley bolt using a 1/2 inch impact wrench (bolt is torqued to 133 lb-ft). Once bolt is removed, use a three-jaw puller or harmonic balancer puller to remove the pulley from the crankshaft snout. Do not pry behind pulley as this will damage the timing cover.
   ⚠The harmonic balancer bolt may be torque-to-yield (TTY). Inspect threads and bolt condition - replace if showing any stretching or damage.
   Torque spec

   Harmonic Balancer Bolt180 Nm (133 lb-ft)
4. 4

   Remove upper and lower timing covers
   Remove all timing cover mounting bolts. There are both 10mm and 8mm bolts securing the cover - note their locations as they differ in length and torque specification. The timing cover interfaces with the oil pan at the bottom; carefully separate this joint. Remove the timing cover by pulling straight outward to avoid damaging the gasket surfaces. Clean all old gasket material from timing cover and engine block using plastic scraper.
   ℹ️Do not rotate crankshaft or camshafts with timing cover removed. Mark timing chain and sprocket positions with paint marker if you need reference points.
   Torque spec

   Cover Bolts19 Nm (14 lb-ft)
5. 5

   Remove front main seal
   Using a front seal puller tool or two small pry bars positioned 180 degrees apart, carefully extract the old front crankshaft seal from the timing cover bore. Work evenly around the seal to prevent cocking it in the bore. Inspect the crankshaft snout surface for any grooves, scratches, or damage where the seal rides. Clean the seal bore in the timing cover thoroughly with brake cleaner and inspect for damage.
   ⚠Do not damage the seal bore in the timing cover or scratch the crankshaft sealing surface. Any grooves will cause the new seal to leak.
6. 6

   Install new front main seal
   Lightly coat the outer diameter of the new seal with clean engine oil. Coat the seal lip with clean engine oil. Position the seal squarely in the timing cover bore with the spring side of the seal facing inward (toward engine). Using a seal driver or appropriately sized socket that contacts only the outer edge of the seal, drive the seal in evenly until it is flush with or slightly below the timing cover surface. Verify the seal is seated evenly around its entire circumference.
7. 7

   Prepare timing cover for installation
   Clean all gasket surfaces on the engine block, cylinder head interface, and oil pan mating surface using plastic scraper and brake cleaner. Ensure no old RTV or gasket material remains. Install new timing cover gasket on the cover or engine block per gasket design. Apply a small bead (3mm) of Motorcraft RTV sealant at the corners where the timing cover meets the oil pan and cylinder head junction points.
8. 8

   Install timing cover
   Carefully position the timing cover onto the engine, aligning it with dowel pins on the block. Ensure the gasket remains properly positioned. Hand-start all timing cover bolts before tightening any. Tighten the 10mm timing cover bolts to 45 Nm (33 lb-ft) in a crisscross pattern from center outward. Tighten the 8mm timing cover bolts to 25 Nm (18 lb-ft) in sequence. Allow RTV sealant to cure for 30 minutes before adding oil.
   ℹ️Follow proper tightening sequence starting from center bolts and working outward to prevent cover warping and ensure even gasket compression.
   Torque spec

   Cover Bolts19 Nm (14 lb-ft)
9. 9

   Install crankshaft pulley/harmonic balancer
   Clean the crankshaft snout and inner bore of the harmonic balancer with brake cleaner. Lightly oil the crankshaft seal surface. Slide the harmonic balancer onto the crankshaft, aligning the keyway with the crankshaft key. Apply a small amount of clean engine oil to the threads and underside of the bolt head. Install the crankshaft bolt and tighten to 180 Nm (133 lb-ft) using an impact wrench or torque wrench. Use holding tool to prevent rotation if using torque wrench.
   ⚠Do not drive the harmonic balancer onto the crankshaft with the bolt. The balancer should slide on with hand pressure. Use a balancer installation tool if needed.
   Torque spec

   Crankshaft Pulley Bolt180 Nm (133 lb-ft)
10. 10

    Reinstall sensors and accessories
    Install crankshaft position sensor into timing cover and tighten mounting bolt to 12 Nm (9 lb-ft). Reconnect electrical connector. Reconnect camshaft position sensor connectors. Install serpentine belt tensioner and tighten mounting bolts to specified torque. Route and install serpentine belt according to routing diagram, ensuring proper engagement on all pulleys.
    Torque spec

    Mounting Bolts54 Nm (40 lb-ft)
11. 11

    Complete fluid service
    Install new oil drain plug crush washer and tighten oil drain plug to 35 Nm (26 lb-ft). Install new oil filter and hand-tighten plus 3/4 turn. Fill engine with 6.0 quarts of Motorcraft 0W-20 full synthetic engine oil. Close radiator petcock or reinstall lower hose. Add Motorcraft Orange Coolant to bring level back to proper mark. Install lower splash shield and engine cover.
    Torque spec

    Oil Drain Plug35 Nm (26 lb-ft)

Reassembly

1. Reconnect negative battery cable and ensure all electrical connections are secure
2. Double-check all fasteners are properly torqued and no tools are left in engine bay
3. Verify serpentine belt is properly seated on all pulleys and tensioner is functioning
4. Check that all drain plugs are tight and oil filter is secure

Verification

• Start engine and immediately check for oil leaks around timing cover and front main seal area
• Monitor oil pressure gauge to verify proper pressure within 3-5 seconds of starting
• Allow engine to warm to operating temperature and check for coolant leaks at timing cover
• Shut off engine and recheck oil level after 5 minutes, top off if necessary
• After first 50 miles, inspect front main seal area and timing cover for any seepage
• Check for proper serpentine belt operation with no squealing or misalignment

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