I buried this info in another thread but was urged to get it here for future reference.
The manual points out 6 points to winterize. This includes the midship and transom drain plugs in the hull. 3 others are on the motor and 1 is on the v-drive.
Apparently not all builds have the drain plug on the starboard side hose as shown in the manual (photo below). If that is the case, just disconnect the hose from the heat exchanger.
The manual also references to blow out the heater, if you have one. My dealer confirmed with Malibu the heater is indeed part of the closed side of the cooling system and therefore does not need to be drained.
Finding the drain tubes the first time is easiest if you remove the engine side panels, but once you know where they are, they can easily be reached without removing the panels.
Winterization on these motors really couldn’t be much easier!
A big shoutout to #Stateamind for clarifying things and providing the winterization diagram, which isn’t found in the manual.
Port side manifold drain tube plug location, with cables shown below. When pulling this plug, you may want to hold the tube and direct water away from the battery cable connection that is somewhat below it, just to be safe. Note, don’t get confused by the oil drain whip that is shown in this photo attached to the lifting eye. The drain tube has the blue plug on it
Starboard side manifold drain tube