service intervals: normal versus severe, and which one you are
your owner's manual has a maintenance schedule, and on most vehicles it has two columns. normal service and severe service.
nearly everybody assumes they are the normal column. most Ontario drivers are not.
what counts as severe service
manufacturers define it, and the definitions are broader than people expect:
- trips under about eight kilometres, especially in cold weather. the engine never reaches full operating temperature, so moisture and fuel stay in the oil.
- extended idling or stop and go traffic
- driving on gravel or dusty roads, which describes a great deal of Elgin County
- towing or carrying heavy loads
- extreme temperatures, hot or cold, and an Ontario winter qualifies
- roof racks, on some manufacturers' definitions
if two or more of those describe your driving, you are on the severe schedule regardless of how gentle your driving feels.
why the distinction matters more on modern cars
intervals got long. oil that was changed every 5,000 kilometres now goes 12,000 or more, which is a genuine improvement in the conditions the interval assumes.
the longer the interval, the more a wrong assumption costs. running the normal schedule on a car doing severe-service driving means oil that is well past its useful life for a substantial part of every cycle.
what is actually on the schedule
beyond oil: air filters, cabin filters, brake fluid, coolant, transmission fluid, spark plugs, and inspections of the brakes, suspension and steering.
some of it is time-based rather than distance-based, which catches out anyone who drives very little. brake fluid and coolant age on a calendar whether or not the vehicle moves.
what we will tell you
which column applies to how you actually drive, and which items on it are genuinely due rather than simply listed at that mileage.
both directions. sometimes the answer is that the schedule says to do something and your vehicle does not need it yet, and we would rather say that than sell it to you.