Thanks for the advice and I been asking mechanic in person, so I understand the differences of top overhaul and major overhaul.
Regarding to the white smoke, it only happens while engine rev from 3k~4k RPM. White? Blue? Black? My mechanic saw it and said it is white
Anyway it will not emit white smoke during normal driving, with RPM < 3k. Sometimes it gives some, but not really noticeable.
I been experince twice overheating, due to radiator internal stuck, luckily it didnt touch the redline in the termometer. But did these overheating destroy my gasket and cause it torn out? Anyhow, the water level in my water reservior drops and I top up them, but volume is less. And not frequent top up, maybe once a month.
So I am thinking to choose the solution
Shall I go for top overhaul to replace the gasket, valve seals etc for the engine top part then to see the result. If the condition is not improved, then I will go for major overhaul, to replace the piston rings.
So if my car is did top overhaul, then go for major overhaul, will it most cost saving? Will the previous top engine overhaul save some cost during the major overhaul?Or it is better to go for major overhaul to resolve them in a shot?