Do you knoe what is the cause of a white smoke when you start the engine and when it is running it is gone and notice of coolant getting low every 2-3 days, I look under but dont see coolant leak.
Well a little white smoke is usual when starting a car. You can get white smoke with a coolant leak into the engine (head gasket ect...) but usually the white smoke doesn't go away in that case. Since you are loosing fluid though it is a possibility. I'd take the car to a mechanic and have the coolant system pressure tested for leak. It's possible to have a leak that will only open up when driving. I've had one that only leaked when the car was under load at speed, which made it impossible to find in my home garage, but it sprayed under pressure which made it easy to find! Have the system pressure tested. If you find the leak, awesome...if not it could be leaking elsewhere(head gasket...). In which case the repair will likely be more than your car is worth, unless you do it yourself that is.
White smoke = Coolent Blue smoke = Oil Black smoke = Fuel It is most likely your head gasket or gaskets if a v style motor(v6,v8,V10).