I have a 2004 G35 coupe and recently smelt a sweet coolant smell. I opened up the hood and found a spray from the cap towards the front of the engine(the car doesnt leak when the car is off, only when its running and pressurized). I replaced cap and found out that wasnt the problem. I bought a pressure tester and tried to diagnosis the problem. however, its not holding pressure because it appears to just go straight to the overflow hose. anyone know how to use one on the G? lol

The leak appears to be underneath the upper hose, but I want to be sure before replacing the hose.

 

You have a thirteen year old vehicle and you are hesitant about replacing a hose?

I would say based on the age of your vehicle go replace the hoses, clamps, thermostat, water pump, coolant flush and belts if you intend to keep your vehicle.

You may also need a radiator.

Telcoman

 

You realize Nissan recommends swaping out radiator fluids every 30K miles? This also includes replacing belts and hoses if needed! It's far better to replace what's needed than to get stuck on the side of the road late at night with everything closed within miles of your location...think about it! Anything I replace always comes from Nissan, I like how there belts, hoses and wiper blades last...just a suggestion!
Gary

 

Just block off the overflow hose with one of those vacuum hose covers or put something in the hose. It could just be a clamp or you can cut of a small section of the old hose and use a new clamp.

 

When you're pressure testing it, you shouldn't be losing any coolant into the overflow unless your radiator cap is not holding pressure properly. At what pressure does it start to leak? If it's less than the rated pressure of the radiator cap then you need a new cap.