What would cause your 11month rottweiler to all of sudden have excessive drooling?

Copious (large) amounts of drooling is a symptom of severe nausea, so it could be that your dog ate something that could be causing him to feel nauseous, or could have ingested poison or antifreeze. Watch him closely to see if he begins to display any other symptoms such as lethargy, disoriented, labored breathing, shallow breathing, fever, cold to the touch, etc.

You also need to check the color of his gums. If they are a very pale color, it could be an indication of shock, and if they are a bluish color, it could be an indication of lack of oxygen.

Keep a very close eye on him, and if he displays any of the above symptoms, get him to the vet ASAP.
Copious (large) amounts of drooling is a symptom of severe nausea, so it could be that your dog ate something that could be causing him to feel nauseous, or could have ingested poison or antifreeze. Watch him closely to see if he begins to display any other symptoms such as lethargy, disoriented, labored breathing, shallow breathing, fever, cold to the touch, etc.

You also need to check the color of his gums. If they are a very pale color, it could be an indication of shock, and if they are a bluish color, it could be an indication of lack of oxygen.

Keep a very close eye on him, and if he displays any of the above symptoms, get him to the vet ASAP.