International - Domestic Transfer, Plus pickup and Left Luggage at Capital Airport Terminal 3.

Arriving at 12:55 from Mongolia (Air China 902). After going through Custom and picking up luggage, I need to leave my luggage at the airport's storage service for 6 nights. Then I will continue my 17:45 domestic flight to Huangshan (Air China 1551). Both arriving and departing flights are at Terminal 3. Are the 4 hours layover sufficient for me to do this International-Domestic transfer and leaving my luggage for storage?