A major part of general maintenance on your 300ZX is changing the oil filter. When it comes to the oil filter, you may need to change it at every oil change. During the 1960s, reusable oil filters were replaced with the now common disposable oil filter. Since then, further improvements have been made, but oil filters still need to be replaced, which is something a weekend mechanic can easily do.
Position car ramps in front of the front tires of your 300ZX and drive the car up onto the ramps. Put on the emergency brake, while the car is on the ramps, to prevent it from rolling backwards.
Place a catch pan under the oil pan drain plug. This plug should be a large bolt sticking out of the bottom of the pan. Remove the oil drain plug bolt with a socket wrench. The size of the bolt may vary slightly and may either be SAE or metric. Allow all the oil to drain into the pan then set the pan aside.
Fit an oil filter wrench over the oil filter. The oil filter is located on the rear passenger's side of the oil pan directly below the engine. It will be a small, cylindrical object protruding from the oil pan.
Turn the oil filter wrench counterclockwise to loosen the oil filter. Remove the filter wrench and twist the oil filter off by hand. Quickly remove the filter and turn it open side up to prevent spilling any oil out of it.
Pour the oil in the filter into the oil drain pan. Dip your finger into the old oil and run a small bead of oil around the outside edge of the new oil filter where it connects with the oil pan. This will help create a seal for the new filter.
Place the new filter in the same location as the old one. Twist it on clockwise until hand-tight.
Fit the oil filter wrench over the new oil filter and tighten it until it is securely seated. Do not over-tighten or it will be difficult to remove at the next oil change.
Place the oil plug into the hole you removed it from, turn it clockwise and tighten it snugly with the socket wrench.
Fill your 300ZX with oil according to the owner's manual. If you do not have a manual, check with the manufacturer or your local mechanic for oil type and amount specifications for your 300ZX. You can also reference repair manuals, such as Chilton's or Haynes, for your year and model 300ZX
Release the emergency brake and back the 300ZX off the car ramps.
