engine
Front Main Seal
for 2015 Ford F-150 3.5L V6 EcoBoost · RWD
Difficulty
Advanced
Time
4.8 h
Tools
14
Steps
15
This procedure covers the removal and replacement of the front crankshaft main seal on the 3.5L EcoBoost engine, requiring removal of the front accessory drive system and timing cover.
Warnings
⚠️Ensure engine is completely cool before starting work. Coolant and oil can cause severe burns.
⚠The crankshaft pulley bolt is extremely tight (133 lb-ft). Use proper holding tools to prevent crankshaft rotation damage.
⚠Do not use metal scrapers on aluminum timing cover surfaces. Use plastic scrapers only to prevent damage.
ℹ️The harmonic balancer bolt is a torque-to-yield (TTY) fastener. Verify Ford service specifications before reuse - replacement may be required.
ℹ️Front timing cover removal requires partial engine lowering or support. Ensure proper engine support before removing motor mounts.
Tools required
Socket set (8mm-21mm)Essential
Torque wrench (10-200 Nm)Essential
Crankshaft pulley holding toolEssential
Front seal removal tool or seal pullerEssential
Front seal installation driver setEssential
Floor jack and jack standsEssential
Oil drain pan (8+ quart capacity)Essential
RTV silicone gasket makerEssential
Gasket scraper (plastic)Essential
Impact wrench (1/2 inch drive)
Engine support bar or hoistEssential
Pry bar (medium)
Brake cleanerEssential
Shop towelsEssential
Parts
- Front crankshaft seal × 1 — Use OEM Ford specification
- Timing cover gasket × 1 — Use OEM Ford specification
- RTV silicone sealant (Motorcraft TA-31) × 1 — TA-31 or equivalent
- Oil drain plug crush washer × 1 — Use OEM specification
- Engine oil filter × 1 — FL-820-S or equivalent
Fluids
- Motorcraft 0W-20 Full Synthetic engine oil — 6 qt
- Motorcraft Orange Coolant — 2 qt
Preparation
- Park vehicle on level ground and engage parking brake
- Disconnect negative battery cable and secure away from terminal
- Allow engine to cool completely (minimum 2 hours)
- Raise and safely support front of vehicle on jack stands
- Remove engine under-cover/splash shield
- Place oil drain pan under engine
- Install engine support bar across engine bay or attach hoist to engine lifting eyes
Procedure
- 1Drain engine oil and coolantRemove oil drain plug and drain engine oil completely into drain pan. Remove oil filter. Drain coolant from radiator petcock and lower radiator hose until level is below timing cover. This prevents coolant loss during timing cover removal.Torque specOil Drain Plug35 Nm (26 lb-ft)
- 2Remove accessory drive belt and componentsUsing a breaker bar on the belt tensioner, rotate tensioner clockwise and remove serpentine belt. Remove belt tensioner assembly. Disconnect power steering pump electrical connector (if applicable) and remove power steering pump mounting bolts, securing pump aside without disconnecting lines. Remove A/C compressor mounting bolts and secure compressor aside without disconnecting refrigerant lines.Torque specMounting Bolts55 Nm (40 lb-ft)
- 3Remove crankshaft pulley/harmonic balancerInstall crankshaft holding tool to prevent rotation. Using breaker bar or impact wrench, remove harmonic balancer bolt (turns counterclockwise). Use harmonic balancer puller to remove balancer from crankshaft snout. Do not pry or hammer on balancer as this will damage it. Inspect balancer for wobble or rubber deterioration.⚠Never use a jaw-type puller on the outer ring of the harmonic balancer. Use only a hub-mounted puller on the center hub to avoid balancer damage.Torque specHarmonic Balancer Bolt180 Nm (133 lb-ft)
- 4Remove front engine mountSupport engine weight with engine support bar or hoist. Remove right-side engine mount-to-frame bolts and engine mount-to-engine bracket bolts. Remove or loosen engine mount to allow clearance for timing cover removal. Lower engine slightly (approximately 1-2 inches) if needed for access.Torque specMounting Bolts55 Nm (40 lb-ft)
- 5Disconnect components from timing coverDisconnect crankshaft position (CKP) sensor electrical connector. Remove CKP sensor mounting bolt and remove sensor from timing cover. Disconnect camshaft position (CMP) sensor connectors if routed on timing cover. Remove any wiring harness brackets attached to timing cover. Tag all connections for reassembly.Torque specSensor Bolts12 Nm (9 lb-ft)
- 6Remove front oil pan section boltsRemove the front section oil pan-to-timing cover bolts only. These are the bolts connecting the oil pan to the front timing cover. Do not remove all oil pan bolts - only those interfacing with the timing cover (typically 6-8 bolts). Leave rear oil pan bolts in place.Torque specOil Pan Bolts12 Nm (9 lb-ft)
- 7Remove timing coverRemove all timing cover bolts in reverse of tightening sequence. There are both 8mm and 10mm bolts of varying lengths - note locations for reinstallation. Carefully pry timing cover away from engine block using plastic pry points. Remove timing cover and gasket. Inspect timing chain, guides, and tensioners for wear while cover is off.ℹ️Take photos of timing cover bolt locations. Bolts are different lengths and must be reinstalled in correct positions.Torque specCover Bolts19 Nm (14 lb-ft)
- 8Remove front crankshaft sealUsing front seal removal tool or seal puller, carefully extract the old front crankshaft seal from the timing cover. Insert tool behind seal lip and pry evenly to avoid cocking the seal. Alternatively, use a slide hammer with seal puller attachment. Clean the seal bore in the timing cover thoroughly with brake cleaner and inspect for damage or scoring.⚠Do not damage the seal bore surface in the timing cover. Scratches or gouges will cause the new seal to leak.
- 9Clean all sealing surfacesUsing plastic gasket scraper, carefully remove all old gasket material and RTV from timing cover mating surface and engine block. Clean oil pan-to-timing cover junction thoroughly. Remove any debris from timing cover bolt holes. Wipe all surfaces clean with brake cleaner and lint-free shop towels. Ensure surfaces are completely dry before reassembly.
- 10Install new front crankshaft sealLightly coat outer edge of new seal with clean engine oil. Coat seal lip with clean engine oil. Using appropriate size seal driver or installation tool, carefully drive new seal squarely into timing cover bore until fully seated and flush with cover surface. Ensure seal is not cocked or damaged during installation. Verify seal is fully seated around entire circumference.⚠The seal must be installed perfectly square. A cocked seal will leak immediately. Use a proper seal driver sized for this seal.
- 11Prepare timing cover for installationInstall new timing cover gasket onto cover. Apply small bead (2-3mm) of RTV silicone at engine block-to-oil pan junction points where timing cover bridges the gap. Apply RTV to oil pan-to-timing cover mating surface. Allow RTV to set for 5 minutes but install cover within 15 minutes of RTV application.
- 12Install timing coverCarefully align timing cover onto engine block, ensuring gasket stays in position. Hand-start all timing cover bolts, ensuring correct bolt lengths in correct positions. Tighten 8mm bolts first in sequence to specification, then tighten 10mm bolts in sequence to specification. Follow factory tightening sequence starting from center and working outward.ℹ️Timing cover bolts must be tightened in proper sequence to prevent cover warping and oil leaks. Consult factory service manual for exact sequence diagram.Torque specCover Bolts19 Nm (14 lb-ft)
- 13Reinstall oil pan section and sensorsInstall front oil pan-to-timing cover bolts and tighten to specification in crisscross pattern. Install crankshaft position sensor with new O-ring if equipped, torque sensor bolt to specification. Reconnect CKP and CMP sensor electrical connectors. Reinstall any wiring harness brackets removed earlier.Torque specOil Pan Bolts12 Nm (9 lb-ft)Sensor Bolts12 Nm (9 lb-ft)
- 14Reinstall harmonic balancer and front mountClean crankshaft snout and harmonic balancer bore with brake cleaner. Lightly oil crankshaft snout. Align harmonic balancer keyway with crankshaft key and slide balancer onto crankshaft by hand. Install harmonic balancer bolt (verify if new TTY bolt required per Ford specifications). Using holding tool, torque bolt to 133 lb-ft. Raise engine into position and reinstall engine mount, torquing all mounting bolts to specification.ℹ️Check Ford service bulletin for your specific build date. Some applications require new harmonic balancer bolt (TTY). Reusing TTY bolts can result in bolt failure.Torque specHarmonic Balancer Bolt180 Nm (133 lb-ft)Mounting Bolts55 Nm (40 lb-ft)
- 15Reinstall accessories and complete assemblyReinstall A/C compressor and power steering pump to their mounting brackets, torquing bolts to specification. Reinstall belt tensioner. Route and install serpentine belt following belt routing diagram on radiator support. Install new oil filter and new drain plug crush washer. Install oil drain plug and torque to specification. Refill engine with 6 quarts of Motorcraft 0W-20 oil. Refill coolant system to proper level. Reinstall engine under-cover. Reconnect negative battery cable.Torque specMounting Bolts55 Nm (40 lb-ft)Oil Drain Plug35 Nm (26 lb-ft)
Reassembly
- Double-check all electrical connectors are fully seated and locked
- Verify serpentine belt is properly seated on all pulleys before starting engine
- Ensure no tools or rags are left in engine bay
- Verify oil level is correct on dipstick after filling
- Check coolant level in reservoir after refilling
Verification
- Start engine and verify no unusual noises from timing cover area
- Check immediately for oil leaks around timing cover, oil pan junction, and front crankshaft seal
- Allow engine to reach operating temperature and verify no coolant leaks from timing cover
- Recheck oil level after engine reaches operating temperature and top off if needed
- Monitor for oil leaks over next 50-100 miles, checking after each drive
- Verify accessory drive belt operation - no slipping, squealing, or misalignment
- After 500 miles, recheck harmonic balancer bolt torque if reused (not applicable if new TTY bolt installed)