I have a 2012 F-250 4x4. I have had the vehicle for about 7 months and have had a few issues since acquisition. I have had the cooler and one of the EGR sensors replaced. My issue is, after shut off, for about 30 seconds I hear a loud whistling followed by a plunger type sound around the driver side front wheel well. I also hear a pump like sound in the rear of the vehicle for the same amount of time, however I think this is the DEF return. Although I can't confirm, I believe the noise started around the time the cooler was replaced; the work order states that they pulled the turbo to replace. My concern that there is an issue with the turbo or some other piece is wrong before the warranty is up. Anyone know what could be wrong? Or is there anything wrong and I'm just letting paranoia get the best of me?

Thank you.