Oil leaking from underneath a washing machine is often caused by a failing transmission. The transmission runs with the help of oil, and, as the component ages, it's more likely to leak oil that may end up on your laundry room floor. Although changes have been made to improve the design of a washer's transmission to prevent oil leaks, leaks are still a problem with machines manufactured before 1995 that are still in use. In addition, oil can sometimes leak from other components that may fall on your machine.
A leaky transmission is more common with older washers built before 1995 prior to the institution of widespread transmission design changes that most appliance manufacturers made to eliminate oil leaks. However, even newer washing machines aren't completely leak free. If a washing machine withstands a fair amount of vibration over an extended time period, the powerful motion can damage its components, including the washer's transmission, and cause it to leak oil. If you suspect that your washer's transmission is leaking, get the washing machine serviced.
Most residential washing machines have a motor assembly that operates with oil much like the transmission does. If the motor fails, it may drip oil, which can pool below your washer. After you discover oil beneath the washer, try to run your washer on a routine wash cycle. If, after starting the machine, you find that the washer won't agitate or spin, the motor assembly has probably malfunctioned. Contact a washer repair technician to evaluate the motor assembly's condition and investigate the oil leak.
Grease encompasses the ball bearing support joint of most washing machines. The bearing is generally located at the bottom of a top-loading washing machine and allows its drum to move in smooth, continuous motions. As the bearing wears, it may drop trace amounts of grease that resemble a brown, oil-like substance, which you may see staining the floor under the washing machine. Usually, when the ball bearing needs more grease, it will squeak and squeal when the drum agitates and spins. Inspect the ball bearing to ensure that it's surrounded by grease, and lubricate it if needed.
Certain washing machines have metal drums that can corrode and rust as they age. If a drum rusts, it can leak water underneath the washer each time you do laundry. Often the water that leaks from a rusty drum is discolored and may even appear as oil upon first inspection. Contact a washer repair technician to examine the washer. If the technician confirms that the drum has corroded, you may want to purchase a new washer as the cost of replacing the drum is roughly the same as the price of a new machine.