My gx335 finally started now loads of white smoke ???

Blow head gasket. Just did one today.

If it's white (not blue-ish) smoke then it's most likely coolant = blown head gasket or cracked block. If it smells sweet at all it's coolant = trouble.

I don't know what a heater plug is...

catalytic converter or o2 sensor maybe

Hi
White smoke is usually a good sign of un-burnt diesel so reading your post and all the things you have already changed ie the glow plugs I would have the injectors tested to make sure they are atomising properly as it sounds to me like when your car isn't under load ie at low revs you have a cylinder that isn't firing correctly
Hope this helps Nick

sounds like engine block is cracked

Sounds like a leaking head gasket.

Your head gasket is leaking and you'll have to take your car to your mechanic, the wihte smoke is coolant leaking into theengine cylinders, check you radiator it's problably low.

Cracked head!!!! Have it pressure tested before reassembly. A reputable motor engineering shop will be able to do this for you.

White smoke is what color exhaust is when your burning antifreeze.The antifreeze is making the plugs wet and hard to start.You need to have your car checked for a head gasket.

I'm guessing this vehicle is a diesel. From your description, it sounds like you may have a fuel system problem, bad fuel injector, bad fuel pressure regulator, or possibly even a problem with the fuel injection pump. The white smoke you spoke of is unburned fuel and you are right the system is flooded and takes a little bit of running to clear out. I would highly reccommend taking your truck to a repair shop. The longer you delay, the more likely that you'll cause additional damage to other systems, for example the starting system and charging system as well as shortening the life of your batteries.