white heavy smoke from car?

It is unburnt fuel due to an ignition component malfunction during cold starting. If you find a garage with an engine analyzer and have them do a scan on the engine ignition and fuel and sensors array, first when hot and running nicely, and then leave it sat at the garage overnight so they can have another go scanning when it's cold in the morning, they should be able to give you a complete picture of what is happening with it, and you would get it sorted rather easily that way.

Hi so the cold petrol engine gets moisture in it's exhaust system over night due to low temperatures this condensation is inside the exhaust pipe. rotting it from the inside .

so when you first start your car two things are happening the engine management system is putting more fuel in so the engine heats up quicker so it then needs to get cold surfaces hot this does produce steam from the condensation which forms within the exhaust. so white smoke which is some unburnt fuel and water vapour is exhausted. the engine management system monitors the temperature all the time changing the fuel to air mixture tilted engine is hot. during which the amount of white smoke gradually reduces to next to nothing depending on how cold it is outside.

Natural gas?? Oops, I have NO previous exposure to natural gas. Propane, yes.

White from exhaust is steam, usually from coolant leak. Often it's a head gasket, but rarely a crack in the cylinder or cylinder head.

Blue from exhaust is oil.

Brown or black from exhaust is unburned gasoline, extreme rich situation, a sweet, strong smell that burns your eyes.

Maybe there's moisture in your gas??

I'm wondering if your coolant is slowly disappearing??