the solution is to raplce your OWV, they need to open your cylinder head, took 3 days at least to replace it.
Look like most of the Preve owner have this Gluk Gluk sound, regardless manual or auto, off aircond, free gear ->N, did't apply a brake, still got sound. Anyone have a solution for this please let us know, if i remember correctly it caused by ABS drag, but confirm

under rare cases your engine oil will be leaking and high fuel consumption, i think you should get confirmation with Proton because no one here know what are the function of OWV, so we cannot theorize the long term/shor term effect, based on kiapreve problem the symptom instead of clak clak sound is oil leaking and high FC.