You'll learn to absolutely hate the cooling system on the GA16DE. There are several hoses that have random positioning points on the engine. Follow the feed hose to the water pump (the one that wraps around the backside of the engine). There should be a hose between the metal pipe and thermostat housing. Check that hose for leaks. There is also a smaller hose that runs from the thermostat housing to the lower intake manifold. It is also prone to leaking, and is a real pain to remove and replace. Don't forget about the throttle-body hoses for cold weather start-up as well. These hoses are the biggest flaw I have found in the GA16DE... whichever Nissan engineer designed it needs to be flogged a few times.