96 nissan altima with ne water pump and thermostat

1. Improper water circulation: Sometimes, eventhough you are sure that you have enough water on your radiator, your car still overheats. It might probably be that the water is cannot circulate properly, which results to improper cooling process. There are several reasons for this which you can discover by yourself. To verify if the water circulates properly, start your engine without the radiator cap. If water circulation is good, you should notice that the water pops smoothly over the top but still retains the amount. Another way to check, detach one of the ends of your radiator hose from your radiator and see if water flows continously over.
If water doesn’t circulates well, check the thermostat if it’s open. It should be open, meaning clean, and the water can pass through it.
If thermostat is clean and still the water doesn’t circulate properly, then you have to check the water pump. That’s probably where the problem is. A little leak on the pump will cause improper flow of water through the radiator system.
If you are sure that the problem is not about water circulation, another thing you can consider is check the engine oil. Very low amount of oil can cause greater friction of the mechanical system of your engine. If it’s not time to change oil yet, you can add over some amount of oil until advisable amount is reached.
While we can’t be always sure about our engine, especially if it’s not new, we should be prepared when it happens. Bringing extra gallon of water in your trunk will surely help.