A cleaner oil change procedure can be achieved by using an adaptor
assembly that comprises: a housing unit that defines a cavity volume; a
filter mount connected to the housing unit, and adapted to mount a
spin-on oil filter; an inner piston slidably engaged with the filter
mount and adapted to fit within the cavity volume, wherein the inner
piston is moveable between a first position within the cavity volume and
a second position substantially outside of the cavity volume; an actuator
spring located between the inner piston and the housing unit, wherein the
actuator spring exerts a force on the inner piston capable of moving the
inner piston from the first position to the second position; a drain
valve slidably connected to the inner piston; a drain channel in the
housing unit; and a valve spring adapted to force the drain valve to seal
against the drain channel and prevent flow of oil through the drain
channel when the inner piston is in the first position, wherein the drain
valve does not seal against the drain channel when the piston is in the
second position.