Musnad Ahmad 5:639

'Abd al-Razzaq narrated to us, from Sufyan, from Abu Ishaq, from Abu Hayyah ibn Qays, from 'Ali: That he performed ablution three times [for each part], then he wiped his head, then he drank the remainder of his ablution water. Then he said: "Whoever is pleased to look at the ablution of the Prophet, may Allah bless him and grant him peace, let him look at this."