Engine Mechanism Troubleshooting

GENERAL INFORMATION.

Typical engine mechanism faults and their possible causes are described below. After a fault is found, eliminate its cause by performing the

appropriate adjustment, repair or replacement of parts and assemblies.

High Engine Oil Consumption

– Oil leak from the engine. Tighten bolts and/or replace gaskets and seals.

– Incorrect oil level reading on the dipstick. Check the oil level on the

vehicle standing on level ground, after the oil has drained into the

oil pan.

– Use of non-recommended engine oil. Use engine oil whose SAE viscosity grade matches the prevailing

vehicle operating conditions (ambient temperature range).

– Severe operating conditions, such as frequent high-speed driving and towing a trailer, naturally lead to increased oil consumption.

– Malfunction of the Positive Crankcase Ventilation (PCV) system.

– Wear of valve stem seals and/or valve guides. Ream the guides to the repair size and install new valves with increased stem diameter and/or replace the seals.

– Broken or worn piston rings, carbon-stuck rings. Replace faulty rings, clean the rings and grooves.

– Incorrect piston installation.

Low Engine Oil Pressure

– Low crankshaft speed at engine idle.

Adjust the idle speed.

– Faulty oil pressure sensor.

– Faulty oil pressure gauge. Replace the gauge.

– Insufficient oil viscosity or oil contaminated with foreign matter. Replace the engine oil with oil of the recommended grade for the prevailing operating conditions. Drain oil contaminated with fuel or coolant and refill with fresh oil.

– Worn or contaminated oil pump.

– Clogged oil filter.

– Loose mounting or clogged oil pump inlet strainer.

– Hole in the oil pump inlet pipe.

– Worn bearing shells. Replace the shells as necessary.

– Cracks or porosity in the oil galleries walls or clogged oil passages. Repair or replace the cylinder block.

– Missing or incorrectly installed oil gallery plugs. Install the plugs.

Engine overheating.

– Coolant leak, leaks in the oil cooler system, expansion tank malfunction. Check the system for leaks and eliminate them. Check the expansion tank, hoses and cap for serviceability.

– Slipping or broken drive belt. Replace the tensioner or belt.

– Thermostat stuck closed. Check the thermostat and replace it if necessary.

– Faulty electric cooling fan.

– Faulty cylinder head gasket. Check and replace if necessary.

The low oil pressure warning lamp is on when the engine is running at

idle.

– Oil lines and/or oil cooler lines clogged. Clean them.

lines.

– Low oil pump pressure.