You attach a pressure test kit to where the radiator cap goes, and pressurize the system. If it holds pressure, it's good.
There's a leak somewhere in your coolant system. Check the radiator and the hoses.
You fill the coolant through the reservoir, and install a pressure tester to check for leaks.
If the car is running hot, check the thermostat. You can test it by simply removing it and holding a cigarette lighter to the center. If it opens, then it is functioning properly. Check your anti-freeze levels. Check for leaks in your radiator, and check that your fan is turning on.
I would check the radiator coolant bottle for cracks and inspect any hoses to bottle.
Check for fuel leaks and proper fuel pressure.
Somtimes the check lights will come back on because the computer in your car has not been reset. Check your manual that came with the car for a solution. If your answer is not in there then take it to a dealership and they'll know how to correct it. To be on the safe side though check for any leaks around the engine and radiator and underneath the car.
Over-obvious answer? Your radiator, or one of your radiator hoses, leaks - badly.
For radiator leaks look for the following signs: The car will overheat Coolant level will frequently drop Pool of coolant or water under the car radiator Obvious leak noted from radiator on starting the car Faulty radiator cap causing the leak
Your car is low on coolant. You need to top off the radiator, wait until the car is cool of course. You may also want to check the system for leaks.
Check the bottom part of your car for leaks. Check all hoses. Check color of exhaust. If it has white color it means you have internal leakage and you need the head gasket again.
Fuel filter could be clogged, fuel pump may be failing. I would also check for leaks.
If your car will not hold water you should first check your radiator for holes and leaks. This should be done with the engine turned off. If you do not find any leaks coming from the radiator and the water stays inside, turn on your vehicle and let it idle. If you notice water leaking from the vehicle while it is running, then your water pump is bad and will need to be replaced.