Hi, a quick update.....
Went to my company car service workshop at AMK Ind Park 2.....the boss upon hearing the sound do not think is gasket head blown....since no coolant leaking, no whitish stains at EO cap, no white smoke from exhaust....
he suspect is the a/c heater problem since sound can only be heard from center dashboard console where the a/c heater is...so he suggested to block water going into the heater and monitor....
will update all again....