How to Change the Oil in a 1999 Harley Softail

by Chris GillilandUpdated November 07, 2017
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Items you will need

  • Oil drain pan

  • Torx socket set

  • Socket wrench

  • Oil filter wrench

  • Engine oil, 20W50 (3 Quarts)

  • Drain plug O-ring

  • Shop towels

Harley-Davidson's Softail motorcycles evoke the image of the rigid-framed motorcycles of yesteryear, but provide the comfort and performance of a modern suspension through the use of hidden shock absorbers. The 1999 Softail series uses the same Twin-Cam 88 motor used in recent models, lubricated by three separate fluids for the engine, transmission, and primary. However, many riders are uncertain of how to to change the motorcycle's engine oil, due mostly to the apparent absence of an oil drain plug. Once the drain plug is located, changing the oil can be done quickly and easily.

Level your bike. Locate the drain plug by following the oil line from the right side of the oil tank to the frame. The oil line is plugged by the drain plug on the underside of the frame between rear shocks. Place an oil drain pan directly beneath the drain plug and remove it with a socket wrench. Pull the dipstick to allow the oil to drain more quickly. Allow the oil to drain completely.

Remove the old o-ring from the drain plug and slip a new o-ring over the plug. Reinstall the drain plug--do not over-tighten--and wipe away any remaining oil from the area around drain plug with a shop towel.

Place the drain pan under the filter. Using the oil-filter wrench, remove and discard the old oil filter. Fill the new oil filter with oil and loosely screw it onto the motor by hand.

Remove the oil tank filler cap and add up to three quarts of oil into the tank. Replace the filler cap and wipe way any oil spills with a shop towel.

Start the motor and loosen the oil filter until a thin bead of oil begins to seep out from between the motor and the filter. Tighten the filter by hand and stop the motor. Wipe away any oil spills with a shop towel.


Warm the motor before draining the oil. Warm oil flows easily and will drain quickly. Stand the bike upright when draining the oil. This will evacuate more oil than leaving it on the kick stand. If you do not feel that you can complete this task, have the work performed by a certified Harley-Davidson technician.


Locate the drain plug while the motor is cold to keep from burning yourself unnecessarily.

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