Engine Diagnosis

PROBLEM SYMPTOM TABLE - ENGINE MECHANICAL SYSTEM

SYMPTOM	PROBABLE CAUSE	REMEDY
Compression is too low	Blown cylinder head gasket	Replace the gasket.
	Worn or damaged piston rings	Replace the rings.
	Worn piston or cylinder	Repair or replace the piston and/or the cylinder block.
	Worn or damaged valve seat	Repair or replace the valve and/or the seat ring.
	Worn or damaged valve guide	Replace the valve guide.
Drop in oil pressure	Engine oil level is too low	Check the engine oil level.
	Malfunction of oil pressure switch	Replace the oil pressure switch.
	Clogged oil filter	Install a new filter.
	Worn oil pump gears or cover	Replace the gears and/or the cover.
	Thin or diluted engine oil	Change the engine oil. Be sure to use the correct viscosity.
	Stuck (open) oil relief valve	Repair the relief valve.
	Excessive bearing clearance	Replace the bearings.
Oil pressure too high	Stuck (closed) oil relief valve	Repair the relief valve.
Noisy valves	Malfunction of lash adjuster (including entry of air into high pressure chamber)	Check the lash adjuster.
	Thin or diluted engine oil (low oil pressure)	Change the engine oil. Be sure to use the correct viscosity.
	Worn or damaged valve stem or valve guide	Replace the valve and/or the guide.
Connecting rod noise/main bearing noise	Insufficient oil supply	Check the engine oil level.
	Low oil pressure	Refer to oil pressure drop symptoms above.
	Thin or diluted engine oil	Change the engine oil. Be sure to use the correct viscosity.
	Excessive bearing clearance	Replace the bearings.
Noisy timing belt	Incorrect belt tension	Adjust the belt tension and/or replace the timing belt.
Excessive engine rolling and vibration	Loose engine roll stopper (Front, Rear) Loose transaxle mount bracket Loose engine mount bracket Loose center member	Retighten.
Excessive engine rolling and vibration	Broken transaxle mount insulator Broken engine mount insulator Broken engine roll stopper insulator	Replace.