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.