[markwb]

Depending on whether or not you have the L67 (supercharged) or the L36 (non supercharged) engine, there are two coolant drain plugs. On the L67, the drain plugs are underneath the front & rear cylinder wall area of the engine block around the mid point of the block. Access from under car. On the L36, the coolant drain plugs are in the area under the water pump outlet. Probably remove right front wheel, wheelhouse panel & extension to gain access.