Excessive Oil Consumption

NOTE: Use the following information to assist in explaining "normal" oil consumption to the vehicle owners. The amount of oil an engine uses will vary with the way the vehicle is driven in addition to normal engine-to-engine variation. This is especially true during the first 16,000 km (10,000 miles), when a new engine is being "broken in" or until certain internal engine components become conditioned. Vehicles used in heavy duty operation (severe service) may use more oil. The following are examples of heavy duty operation:
- Taxi cab applications
- Police service application
- Severe loading applications
- Sustained high speed operation

When the piston moves downward, a thin film of oil is left on the cylinder walls to lubricate the upper rings. The thin film of oil is burned away on the firing stroke during combustion. Efficient engines will use some oil or they would quickly wear out due to a lack of lubrication. As the vehicle is operated, some oil is drawn into the combustion chambers past the intake and exhaust valve stem seals and burned. For an efficient engine, the amount of oil lost or burned is minimal. The average amount of oil burned should be approximately 1,440 km (900 miles) per 0.9 liter (1 quart) of oil.

Several conditions can affect oil consumption rates. The following is a partial list of these items:
- Engine size
- Operator driving habits
- Ambient temperature

Quality and viscosity of the oil Operating under varying conditions can be frequently misleading. A vehicle that has been run for several thousand kilometers (miles) of short trip operations or below freezing ambient temperatures, may have consumed an acceptable amount of oil. However, when checking the engine oil level, it may measure up to the full mark on the oil level dipstick due to dilution (condensation and fuel) in the engine crankcase. The vehicle then might be driven for a long period of time at high speeds on the highway where the condensation and fuel boil off. The next time the oil is checked, it may appear that a quart of oil was used in a hundred or so miles. This perceived 160 kilometers per quart (100 miles per quart) consumption rate causes customer concern even though the actual oil consumption rate could have been about 2400 kilometers (1500 miles) per quart.

Make sure the selected engine oil meets the recommended API performance category "SG" and SAE viscosity grade as shown in the vehicles Owner Guide. It is also important that the engine oil is changed at the intervals specified for the typical operating conditions of the vehicle.