In general, yes a coolant leak in a 2002 Bonneville can be fixed. The issue whether it is worth the money to fix the leak.
If the coolant is leaking from an upper or lower coolant hose, the repair is simple and inexpensive. If the coolant leak is from the radiator, it will be a bit more difficult and/or expensive to repair. Moving up the scale, if the coolant leak is coming from a manifold gasket, it will be still more expensive. Likewise for a coolant leak from the heater core.
And at the upper end of the scale, if you are leaking coolant from a cracked engine block, you're looking at replacing the engine.
Mine is in the timing chain cover gasket. You can find your leak by pressure testing your coolant system.
A leak in a coolant system can usually be fixed by replacing a hose. If the leak is at the end of the hose, a new clamp might be necessary. If the radiator is leaking, the radiator might need to be replaced.
pressurize the system. that'll make the leak leak faster and you should be able to find it easier.
If there is a coolant leak that is caused by the bleeding screw, the screw is probably stripped and needs to be replaced. The screw can also be wrapped with plumber's tape and screwed back in until the leak can be fixed.
pressurize the system
Have it pressure tested, the intake gaskets have probably failed.
I wouldn't even use it once, get the problem fixed.
You have a coolant leak.You have a coolant leak.
This depends on where the leak is. A hose could be loose or broken or there could be a radiator or engine leak. The area of the leak needs to be found to be able to diagnose.
have the coolant system pressure tested to help diagnose your problem.
The coolant will normally leak into the oil or into the cylinder
Because some opening formed which is allowing coolant to leak out.