She took part in the Egyptian–Ottoman War (1839–1841), also known as the Second Syrian War, when the British Mediterranean Fleet under Admiral Sir Robert Stopford, supported the Ottoman Empire and took action to compel the Egyptians to withdraw from Beirut. During the Oriental Crisis of 1840 "Castor" was involved in the bombardment of St. Jean d’Acre on 3 November 1840. Four sailors (Seamen John O'Brein, Silneck Thomas, Smith William and Weaver Frederick) were killed on board at the capture of St. Jean D'Acre. They were buried in Malta, in the Msida Bastion Cemetery and Historic Garden, Floriana, Malta, where a monument is still visible. After cruising on the coast of Ireland she was sent out to the East Indies Station; before being decommissioned at Chatham in 1842.