The drain plug for the engine oil on a 1987 Suzuki Samurai is located on the
bottom of the engine block, towards the front. It's fairly low down and you'll likely need to get under the vehicle to access it. Be aware that it's a fairly small plug, and it's often difficult to see without a good light.
It's advisable to consult a repair manual specific to your 1987 Suzuki Samurai engine (likely a 1.3L G13B) for a precise visual location. A picture in the manual will greatly aid you.
