Engine - Normal Oil Consumption
89ford06
Article No. 89-9-10
OIL CONSUMPTION - NORMAL USAGE - OWNER INFORMATION
FORD: 1986-89 ALL FORD LINES
LINCOLN-MERCURY: 1986-89 ALL LINCOLN-MERCURY LINES
MERKUR: 1986-89 ALL MERKUR LINES
LIGHT TRUCK: 1986-89 ALL LIGHT TRUCK LINES
ISSUE: The following information can be used to inform vehicle owners about "normal" oil consumption in today's engines.
ACTION: Use the following information to assist in explaining "normal" oil consumption to 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 7500 miles (12000 kilometers), 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:
^ Trailer towing applications
^ Taxi cab applications
^ Police service applications
^ Severe loading applications
^ Sustained high speed operation
Engines need oil to lubricate the following internal components:
^ Engine block cylinder walls
^ Pistons and piston rings
^ Intake and exhaust valve stems
^ Intake and exhaust valve guides
^ All internal engine components
When the pistons move downward, a thin film of oil is left on the cylinder walls. The thin film of oil is burned away on the firing stroke during combustion. If an engine burned a drop of oil during each firing stroke, oil consumption would be about one (1) quart for every mile traveled. Fortunately modern engines use much less oil than this example. However, even efficient engines will use some oil or they would quickly wear out. Additionally as the vehicle is operated, some oil is drawn into the combustion chambers past the intake and exhaust valve stem seals and burned.
A lot of different things 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
Operation under varying conditions can be frequently misleading. A vehicle that has been run for several thousand miles (kilometers) of short trip operation or below freezing ambient temperatures, may have consumed a "normal" amount of oil. However, when checking the engine oil level, it may measure up to the full mark on the dipstick due to dilution (condensation and fuel) in the engine crankcase. The vehicle then might be driven at high speeds on the highway where the condensation and fuel boil off. The next time the engine oil is checked, it may appear that a quart of oil was used in a hundred or so miles. This perceived 100-mile per quart (160-kilometer per quart) oil consumption rate causes customer concern even though the actual overall all oil consumption rate was about 1500-miles per quart (2400-kilometers per quart).
Make sure the selected engine oil meets the recommended API performance category "SG" and SAE viscosity grade as shown in the vehicle Owner Guide. It is also important that the engine oil is changed at the intervals specified for the typical operating conditions of the customer. This information is available in the Owner Guide, Maintenance Schedule and Record log.
OTHER APPLICABLE ARTICLES: None
SUPERSEDES: 86-11-16, date 6/5/86
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 4100