Excessive or Unusual Noise

Excessive or Unusual Noise

Often, engine noises are actually coming from engine accessories rather than from the engine itself.   It can be a very hard to diagnose problem.

Noisy Fan Belt:

  • Incorrect belt that doesn’t fit the pulley grooves.
  • Worn, torn, burned belts.
  • Belt or pulley gummed up.
  • Broken or bent or misaligned pulleys.

Noisy Timing Gears:

  • Chipped gear tooth.
  • Gears loose on hubs or shafts.
  • Timing gears incorrectly aligned.
  • Teeth meshed too tight.
  • Too much clearance in front camshaft.
  • Too much camshaft or crankshaft endplay.

Noisy Pistons

  • Bad fuel.
  • Overheated engine.
  • Worn or broken piston ring land.
  • Incorrectly installed piston pin.
  • Worn or loose piston pin or bushing.
  • Lack of lubrication.
  • Misaligned connecting rods.
  • Excessive rod bearing clearance.
  • Excessive side clearance of piston rings.
  • Undersized piston installed.
  • Worn or broken rings, cylinder walls, or low ring tension.
  • Tapered cylinder bores.
  • Piston 180 degrees out of position.

Noisy Rod Bearings:

  • Excessive clearances.
  • Diluted oil.
  • Low oil pressure.
  • Worn crankpin.
  • Misaligned connecting rod caps.
  • Rod bolts incorrectly torqued.

Noisy Main Bearing:

(Indicated by a knock when engine is accelerated.)

  • Excessive bearing clearances drive belt tension or crankshaft endply.
  • Distorted crankshaft.
  • Loose crankshaft pulley.
  • Loose flywheel or torque converter.
  • Low or diluted oil.
  • Low oil pump pressure.
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