Engine Code Location

1971 Mercury Cyclone Base, 6.6L Eng VIN S, Automatic Trans, Trans Mfr CD FMXSECTION Engine Code Location

Engine code letter (or number designating low compression engines) is fifth  digit in eleven-digit vehicle warranty number stamped on plate on rear face of left front door (second line on plate in 1966, top line on plate in 1967).

NOTE: For official title and registration purposes, this number is stamped on top upper flange of left fender apron, on top surface of radiator and front fender apron support, on tab attached to top weld flange of dash panel, or other location in engine compartment.
RENDER: 1.0x

NO RELATED

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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.