How often should an oil filter be changed?
A.
As often as is necessary to keep the oil clean. The service interval
can vary depending on the number of miles driven, the type of diving,
the type of engine (gasoline or diesel), the mileage on the engine, the
type of oil in the engine and the type of oil filter.
The goal is to change the oil before it undergoes viscosity breakdown, or develops harmful acids and sludge in the crankcase.
Short
trip stop-and-go driving, especially during cold weather and especially
in high-mileage engines with more blowby, causes condensation to build
up rapidly in the crankcase.
If the car isn’t driven far enough or
long enough to heat up the oil and drive off the accumulated moisture,
sludge can start to form inside the engine.
Oil filters can remove
solid particles, but they can’t remove acids or moisture from the oil.
Consequently, if the oil and filter and not replaced, the engine can
sludge up and possibly fail.
The general rule is to always change
the oil filter when the oil is changed. The most common aftermarket
recommendation is to change the oil and filter every 3,000 miles or
every six months (if a vehicle is driven less than 3,000 miles during
this period of time).
Vehicle manufacturers, on the other hand, are more liberal about oil changes.
Some
recommend changing the oil and filter every 5,000 to 7,500 miles — or
even longer. Some maintenance reminder lights may not come on until
10,000 to 15,000 miles! It should be noted, however, that many of these
extended drain intervals are based on using high quality synthetic oil,
not conventional motor oil. It should also be noted that some vehicle
manufacturers have experienced engine sludging problems as a result of
extending oil change intervals too far).
OEM filter replacement
intervals are usually based on “ideal” operating conditions, which
means mostly highway driving, trips that are at least 6 or more miles
in duration, limited idling and not a lot of stop-and-go city driving,
infrequent short trips (especially during cold weather), little or no
driving on dusty gravel roads, and no trailer towing.
The OEM
filter replacement intervals are also designed to minimize maintenance
expense for the vehicle owner. That looks good on paper, but in the
real world it can sometimes result in expensive engine wear and costly
repairs.
Q. What type of oil filter should I use?
A. Many
oil filter suppliers offer a range of filter types within their product
lines. Typically, there is a “standard” replacement oil filter and an
upgrade premium filter that offers extended service life, a finer
filter media or both.
Premium grade filters typically include a
higher efficiency and/or extended life filter media, and are often made
with stronger tubes, end caps and canisters. The premium filter media
helps keep the oil cleaner longer.