Towards the end of season 7, Crowley enters into a contract with Dick Roman (the leviathan) to share parts of the U.S./Canada with Crowley. It seems that helping the Winchesters by giving them his blood would be breaking that contract. So, did Crowley break the contract, or did I misunderstand the terms of the contract they wrote up?
In many episodes Crowley writes his contracts with a huge range of loop-holes. In this situation it was just another Crowley-like contract where there is only one winner (Crowley himself).