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HOMESERVICE MANUALSACURA2015MDX BASEREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE MECHANICALMECHANICALENGINE CONTROL AND ENGINE MECHANICAL - SERVICE, TESTING AND TROUBLESHOOTING (EXCEPT HYBRID)REPAIR REGENERATIONVALVE SEAT RECONDITIONINGRECONDITIONING
2015 Acura MDX Base

Valve Seat Reconditioning: Reconditioning

2015 Acura MDX BaseSECTION Reconditioning
  1. Valve Seat - Reconditioning
    GHH320127Courtesy of HONDA, U.S.A., INC.
    		 1. Inspect valve stem-to-guide clearance . If the valve guides are worn, replace them 

    before cutting the valve seats.

    2. Renew the valve seats in the cylinder head using a valve seat cutter.

    3. Carefully cut a 45 ° seat, removing only enough material to ensure a smooth and concentric seat.
    GHH320128Courtesy of HONDA, U.S.A., INC.
    		 4. Bevel the upper and lower edges at the angles shown in the illustration. Check the width of the seat and adjust accordingly.

    5. Make one more very light passes with the 45 ° cutter to remove any possible burrs caused by the other cutters.

    Valve Seat Width 
    Standard (New):  1.25-1.55 mm (0.0492-0.0610 in)
    Service Limit:  1.55 mm (0.0610 in) 
    GHH320129Courtesy of HONDA, U.S.A., INC.
    		 6. After resurfacing the seat, inspect for even valve seating: Apply Prussian Blue compound (A) to the valve face. Insert the valve in its original location in the cylinder head, then lift it and snap it closed against the valve seat several times.

    7. The actual valve seating surface (B), as shown by the blue compound, should be centered on the valve seat:

    • If it is too high (closer to the valve stem), you must make a second cut with the 67.5 ° cutter (intake seat) or 60 ° cutter (exhaust seat) to move it down, then one more cut with the 45 ° cutter to restore seat width.
    • If it is too low (close to the valve edge), you must make a second cut with the 30 ° cutter to move it up, then make one more cut with the 45 ° cutter to restore valve seat width.
    NOTE: The final cut should always be made with the 45 ° cutter.
    GHH320130Courtesy of HONDA, U.S.A., INC.
    		 8. Insert the intake and exhaust valves in the cylinder head, and measure valve stem installed height (A).

    Intake Valve Stem Installed Height 

    Exhaust Valve Stem Installed Height 

    9. If valve stem installed height is over the service limit, replace the valve and recheck. If it is still over the service limit, replace the cylinder head; the valve seat in the head is too deep.
    Standard (New):  46.93-47.73 mm (1.8476-1.8791 in)
    Service Limit:  47.73 mm (1.8791 in) 
    Standard (New):  47.10-47.90 mm (1.8543-1.8858 in)
    Service Limit:  47.90 mm (1.8858 in) 
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.