I just got a new engine installed in my G37 sedan. Six weeks later, the alternator fails. I've brought the car back to the place that installed the engine and they say all is good with the engine, belts etc. and original alternator simply failed. Fair enough! The only thing is, since I got the car back, there had been a sound like an electric cart when I drive slowly and turn corners. Clearly it's related to the new engine but is it an issue? I was going to mention this next time I brought the car in but it didn't seem to be causing any problems.

 

Electric cart? Not NEARLY enough info here. I My first thought is that an electric carts use straight-cut gears which are quite noisy/whiny.

 

noise when you turn corners?

wheel bearing(s)?