i have got a coopers O ring fitted fella!mine is weeping down the side of the block and i am in the same situation as u!!!!as far as i have managed to find out the burtons ones are copies!i fitted one to my car when i first brought it years ago(had the same problem!)the rings did not fit probably!eyc the goode is a gen one as far as i can make out!if i repair mine i will get a goode one