Do not have your car on.
First step is to make sure your car has enough engine coolant, if you are low, buy some at the store and put it in its proper place for your car(If you do not know where that is then consult your owner's manual for engine or engine coolant.)
If that is not the problem, then it is possible that you have a leak somewhere from the coolant container to your engine. Either check for any possible holes or loose connections or take it into an auto repair shop.
Normally it will last the life of the engine. However if the engine overheats the gasket can be ruined immediately.
Oil on engine burning as engine overheats. Sort of common sense, don't ya think?
If your engine overheats, you should not continue to drive the vehicle, as this can cause severe damage. Instead, safely pull over to the side of the road and turn off the engine to prevent further overheating. Wait for the engine to cool down before attempting to open the hood or check coolant levels. It's advisable to call for roadside assistance if you're unsure how to proceed.
The life of the engine unless the engine overheats.
Your question is not clear...
My 2001 Nissan frontier 3.3 v6 engine is overheating. I changed the thermostat but it still overheats.
There is no way of saying for sure. As long as the engine never overheats and you change the coolant every 50,000 miles it should last the life of the engine.
Ruin it if it overheats with no lubricantProbably seize
You can blow a head gasket or the head can crack or be warped.
Hard driving can cause an engine to use oil, but not drastically. Coolant level should not be effected unless the engine overheats.
If an engine overheats the metal parts expand and the engine will seize up. A seized engine is usually unrepairable.
Anytime the engine overheats you have the possibility of blowing the head gasket.