One problem related to engine rattling and whining sounds has been reported for the 2012 Nissan Sentra. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 Nissan Sentra based on all problems reported for the 2012 Sentra.
The issue first started last summer. I had a car full of 4 teenagers and we were heading out of town and the engine began a loud whistle sounds and then the gas pedal quit working - we limped off the highway after almost getting hit and got a tow truck and rental car. The mechanic had us pay for a whole new motor. We thought the issue was fixed. Then a couple months later I again had 4 teenagers in my car heading out of town and the whistle noise started about an hour into the trip. Then it got louder. Then the car would decelerate going uphill. Then, as we got to the next exit, the gas pedal stopped working completely. We again almost died, barely made it to the gas station and realized there was an auto zone next door. So we went and had the codes read as the check engine light had just popped on. . . When I turned the car back on, everything worked fine but it had sat for 30 minutes. Research led us to the cvt issues with an extended warranty that had passed. We tried a transmission cooling device and did not drive the car over an hour. But this past week I tried again with 2 teenagers in my car. . . One hour in to a trip, it happened again. This is not ok for a car transmission to decelerate and put my children and my life at risk.