- When should I change my motor oil?
The vehicle manufacturer's recommendations should be followed as
a minimum maintenance guide. To have the engine wear slower
use the "severe duty" schedule, which is the usual use condition in
New Jersey. As a practical matter, change the motor oil before it
shows black on the dipstick. Black oil, rather than light
brown, means the oil filter is in bypass and engine wear and sludge
deposits will result. 5,000 miles maximum interval is my
- Why should I change my transmission fluid?
As the 2nd most expensive vehicle component, the transmission is
also cooled, lubricated, and in the case of automatic transmissions,
operated by special oil. This oil will oxidize over time, as
will motor oil. Oxidation will make the oil too thick when
cold and too thin when hot. Metallic debris also accumulates
in transmissions and must be removed from fluid, magnets, and pans.
Debris clogs filters in automatic transmissions causing reduced
pump pressure and, in extreme cases, clutch slippage destroys the
unit. Debris also causes high wear rates, reducing the life of
transmissions. Manufacturers are trying to extend and
eliminate transmission fluid changes, but for now, changing fluid,
cleaning, and replacing filters aggressively is the consumer's best
defense against failure of these units. Most manufacturers are
designing for a life of 150,000 to 200,000 miles. To achieve this
life span, a good policy is to service your transmission every
25,000 to 50,000 miles. This is in line with the "severe"
service schedule of most vehicle manufacturers.
- Should I use synthetic motor oil?
Synthetic motor oil is becoming more accepted in spite of the
expense and it does offer certain benefits compared to
"conventional" motor oil. In particular, synthetic oil resists
oxidation better and provides low friction/low wear benefits.
Conventional oil, however, has been continually improved by
additives and now provides much better protection than 10 or 15
years ago. One thing neither oil can prevent, however, is
contamination by soot and combustion by products. Which ever
oil you choose, its change interval is limited to the oil filter's
capacity. Oil should be changed before it's color turns black
from suspended grime.