Severe Operating Conditions Defined

Starting Model Year 1992:
As a result of technical product enhancements, improved engine management systems, and upgraded fuels and lubrications, true cases of severe operating conditions will rarely exist in non-commercial passenger car applications. For a vehicle to qualify for severe operating conditions the following criteria must be met:

- More than 50 % short distance driving (less than 5 miles/8 km per trip), combined with engine operating at a temperature of less than 176° F (80° C), especially at low outside temperatures.
- More than 50 % operation in lower gears combined with high engine load (mountain driving, poor roads, etc.).

If these requirements are met, it is recommended that an additional oil change (without oil filter change) be performed between the scheduled engine oil change intervals, i.e. engine oil change every 2,500 miles or 3,750 miles, depending on model. (Note: Vehicles that are only occasionally exposed to severe operating conditions do not require an additional oil change).

Model Year 1981 through 1991:
In case of severe operating conditions or heavy use in mainly city traffic or over short distances, frequent mountain driving, poor roads, dusty and muddy conditions, trailer towing, hard driving, etc., it may be necessary to carry out maintenance work at shorter intervals, i. e.:
- Oil and filter change: Half the normally recommended interval.
- Automatic transmission: Fluid change (without filter change) every 15,000 miles/24,000 km.
- Inspect tires.
- Clean or replace air cleaner element.