your wife
It would help to specify the type of noise and type of vehicle in question.
Check the idler pully.
You probably have something wrong with your engine, or brakes. You should really have that checked.
You are hearing a whirring when accelerating first to fourth because you are accelerating too fast and the whirring noise results. If you accelerate normally then you won't hear the whirring sound.
Cadillac does not make a minivan, the closest they have to a minivan would be the SRX Crossover. They have made some concept minivans but never brought any to production.
If this is a general noise, it could be the transaxle. When you are accelerating, the engine is pushing the gears, and when you let go of the pedal, the vehicle starts to shift back down. If this is an engine noise, it could be predetonation or a valve problem.
Noises are impossible to correctly diagnoise unless heard. Take it to a garage.
Answer Humming noise from front endI just got my car fixed with the same problem and it was the wheel bearing and it is gone. Was it a fwd car?
if the car is rear wheel drive, sounds like a u-joint. If it is front wheel drive, sounds like a cv joint. It could also be your engine mounts wearing out. If the rubber insulation has worn out then the engine will shift slightly against the mount and make a clunking noise. This happened on my 96 Nissan Quest minivan.
That's just the rev of the car. This means you are accelerating too fast. Go nice and steady.
Vacuum leak? Check valve on power brake booster?