Nissan Repair: Overheating, radiator cap, cold engine

Question
I replaced my Thermostat twice and my Nissan 2001 Frontier is still overheating could it be my water pump how would I check it. How hard is it to install a water pump?

Answer
Hi Paul -

There is a chance that the pump is the culprit, but that is rare. With the engine warmed up (thermostat open) can you see the water circulating when you remove the radiator cap? Please start with a cold engine, remove the cap and then start it to operating temperature. The thermostat should open after a few minutes and you should see the coolant circulating in the radiator. If that is so, the pump is OK.

Can you tell me the nature of overheat? Does it run and overheat in a few minutes, or only when under load such as climbing hills, on the freeway? Or in stop and go traffic?

This will help the diagnosis -

Hope this helps and let me know -
aloha
calvin