Timing Chain Tensioner

Replace the timing chain tensioners on the 5.0L Coyote V8 engine to restore proper timing chain tension and prevent engine damage from excessive chain slack.

Warnings

Tools required

Parts

• Left timing chain tensioner × 1 — Motorcraft CK-4N144
• Right timing chain tensioner × 1 — Motorcraft CK-4N144
• Timing cover gasket set × 1 — Use OEM specification
• Valve cover gaskets (left and right) × 2 — Use OEM specification
• Crankshaft front seal × 1 — Use OEM specification
• RTV silicone sealant (Motorcraft TA-357) × 1 — Motorcraft TA-357
• Engine oil and filter × 1 — Motorcraft FL-500S

Fluids

• Motorcraft 0W-20 Full Synthetic — 7.5 qt
• Motorcraft Orange Coolant — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable and wait 10 minutes for airbag system to deplete
3. Remove engine cover and air intake assembly
4. Drain engine oil completely into appropriate container
5. Drain coolant from radiator and engine block into appropriate container
6. Remove radiator fan shroud and cooling fan assembly
7. Remove serpentine drive belt and belt tensioner
8. Remove alternator and set aside with wiring attached
9. Remove power steering pump and set aside with lines attached
10. Remove both valve covers completely

Procedure

1. 1

   Remove crankshaft pulley
   Install crankshaft holding tool to prevent rotation. Using a breaker bar, remove the crankshaft pulley bolt (turn counterclockwise). Use a harmonic balancer puller to remove the crankshaft pulley from the crankshaft snout. Be careful not to damage the crankshaft position sensor reluctor ring.
2. 2

   Remove timing cover
   Remove all timing cover bolts in reverse of tightening sequence, noting the different bolt lengths and locations. Carefully separate the timing cover from the engine block using a plastic pry bar at designated pry points. Do not damage the gasket sealing surfaces. Remove and discard the old gasket and front crankshaft seal.
3. 3

   Rotate engine to TDC cylinder 1
   Manually rotate the crankshaft clockwise using a socket on the crankshaft bolt until cylinder 1 is at Top Dead Center (TDC) on the compression stroke. Verify that the timing marks on both camshaft sprockets align with the cylinder head mating surfaces, and the crankshaft keyway is at 12 o'clock position. Mark all timing chain and sprocket positions with paint or marker for reference.
   ℹ️Take photographs of timing mark alignment for reference during reassembly.
4. 4

   Remove left timing chain tensioner
   Locate the left (driver side) timing chain tensioner on the front of the left cylinder head. Remove the tensioner mounting bolt while controlling the tensioner. Carefully remove the tensioner assembly, noting the spring-loaded mechanism. Inspect the tensioner arm and guide for wear or damage.
   ⚠The tensioner is spring-loaded. Control it during removal to prevent it from flying out.
5. 5

   Remove right timing chain tensioner
   Locate the right (passenger side) timing chain tensioner on the front of the right cylinder head. Remove the tensioner mounting bolt while controlling the tensioner. Carefully remove the tensioner assembly. Inspect the tensioner arm and guide for wear or damage.
   ⚠The tensioner is spring-loaded. Control it during removal to prevent it from flying out.
6. 6

   Inspect timing chain and guides
   With tensioners removed, inspect both timing chains for excessive wear, stretching, or damaged links. Check timing chain guides and rails for scoring, cracking, or excessive wear grooves. Measure timing chain slack if a dial indicator is available (should not exceed 6mm). Replace chains and guides if any wear is evident.
   ℹ️While tensioners are the primary failure point, always inspect chains and guides for wear during this service.
7. 7

   Prepare new timing chain tensioners
   Remove new tensioners from packaging. Using a tensioner compression tool or small C-clamp, carefully compress each tensioner piston fully into its bore. Insert the retaining pin or clip through the tensioner body to lock it in the compressed position. Verify the tensioner ratchet mechanism moves freely.
   ⚠Tensioners must be compressed and pinned before installation or they will not fit properly.
8. 8

   Install new left timing chain tensioner
   Verify cylinder 1 is still at TDC and timing marks are aligned. Position the new left tensioner (still compressed with pin installed) into place on the left cylinder head. Install the mounting bolt and torque to specification. Do NOT remove the retaining pin yet.
9. 9

   Install new right timing chain tensioner
   Position the new right tensioner (still compressed with pin installed) into place on the right cylinder head. Install the mounting bolt and torque to specification. Do NOT remove the retaining pin yet.
10. 10

    Release tensioners and verify timing
    Remove the retaining pins from both timing chain tensioners, allowing them to apply tension to the chains. Manually rotate the crankshaft two complete revolutions clockwise. Verify that all timing marks realign correctly at TDC cylinder 1. Check that timing chains have proper tension with no excessive slack.
    ⚠If timing marks do not realign after two revolutions, do not continue. Disassemble and verify correct installation.
11. 11

    Clean and prepare timing cover
    Thoroughly clean all gasket surfaces on the timing cover and engine block using a gasket scraper. Remove all old RTV silicone and gasket material. Clean surfaces with brake cleaner and wipe dry. Install new crankshaft front seal into timing cover using a seal driver. Apply thin bead of RTV silicone to specified areas per factory service manual.
12. 12

    Install timing cover
    Position new timing cover gasket onto engine block. Carefully install timing cover, ensuring it seats properly over crankshaft snout and dowel pins. Install all timing cover bolts finger-tight, noting correct bolt lengths and locations. Tighten bolts in proper sequence: 8mm bolts first to specification, then remaining bolts to specification.
13. 13

    Install crankshaft pulley
    Clean crankshaft snout and pulley bore thoroughly. Align crankshaft pulley keyway with crankshaft key and slide pulley onto crankshaft. Install new crankshaft pulley bolt. Using crankshaft holding tool to prevent rotation, torque bolt to specification using a torque wrench.
14. 14

    Reinstall valve covers and accessories
    Install new valve cover gaskets onto valve covers. Position valve covers onto cylinder heads and install bolts finger-tight. Torque valve cover bolts in proper sequence from center outward to specification. Reinstall power steering pump, alternator, belt tensioner, and serpentine belt. Reinstall cooling fan assembly and shroud.

Reassembly

1. Reinstall air intake assembly and engine cover
2. Refill engine with 7.5 quarts of Motorcraft 0W-20 full synthetic engine oil and new oil filter
3. Refill cooling system with Motorcraft Orange coolant to proper level
4. Reconnect negative battery cable
5. Verify all electrical connectors, hoses, and components are properly reconnected

Verification

• Start engine and verify no oil or coolant leaks around timing cover and valve covers
• Listen for any unusual timing chain noise (rattling or slapping) at idle and during acceleration
• Verify engine idles smoothly with no misfires or rough running
• Check engine oil pressure gauge shows normal pressure
• Allow engine to reach operating temperature and verify cooling system operates normally
• Rev engine to 2500 RPM several times and verify smooth operation with no chain noise
• Scan for diagnostic trouble codes and verify none are present
• Road test vehicle and verify normal acceleration and engine performance

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