remove your spark plugs n cranck over your car... if its a head gasket it might spray out some water,,, if none comes out get a mechanic to COMPRESSURE test it... but when u get that done... take the radiator cap off fill the water all the way to the top, then comp test it... if the water in the radiator Bubbles in any way its a head gasket....
anyways before u said u had creamy stuff in the motor n the dip stick... the car might have got hot n cracked the head... after a while the head might have KINDA repaired itself but heat... the crack will fix cause the block will expaind from the heat...
last of all... is it using much water a week??? hope all is good man n best of luck...
