Why 4jx1 engine loud knock and white smoke comes

SOURCE: White Smoke From Tail Pipe/Exhaust

It often means that you are burning antifreeze. You asked if it needs antifreeze, have you noticed any leaking out of the reservoir tank while you are running it? Sometimes when the head gasket goes it will produce a passage for the antifreeze to pass from the capillaries into the combustion chamber. It is easy to check if you have an air compressor. Remove one of the rear sparkplugs and the radiator cap. Fill the radiator and then push some air into the sparkplug hole (get a good seal in case a valve is open). Repeat with all the cylinders and watch for air bubbles coming up into the radiator. If bubbles come up or fluid is pumped out, the head gasket is blown and must be replaced. It is more likely to happen at the back of the engine because it is farthest away from the fan and therefore gets less cooling. Also check your oil for discoloration. If it is a brownish color it could mean your oil and antifreeze are mixing and has the potential to damage your bearings