From crash.net :

Ferrari has confirmed that the decision not to change Kimi Raikkonen's engine between the Australian and Malaysian grands prix may have cost the Finn the chance to take second place at Sepang last weekend. Raikkonen was forced to rein in his F2007 on the way to victory in Melbourne after the team discovered that his V8 had developed a water leak, but subsequent simulations of the problem in testing showed that the fault would not have been terminal, prompting the Scuderia to continue with the motor in Malaysia rather than take a grid penalty for changing it.

Well, do they seriously believe he had better chances for winning or taking 2nd place if he had got a 10 place grid penalty ?