 I too had the mysterious cluck in the front steering, air conditioning problem. After 5 times in the shop, The factory reps came in and looked at the car,gave me extended war. They said the noise was normal.  When I picked up the car, the next day the engine blew at 30,000 miles. They said the car had no oil, but the oil light never came on. Took several weeks with Nissan to get the dealer to fix the car.  We only have 5,000 miles left on warr. Don't want the car anymore. No one can tell me where the oil went and why the light never came on.