today when I turn my car off I heard this noise coming from somewhere in front of the engine and it sound like a helicopter. I turn the car back on and turn it off again to see if I would hear the same sound again but nothing so i drove it around and turn it off but nothing again and this is the first time I hear this sound.
so what you guys think it is? I am thinking is a fan but dont know which, I am not 100% sure is a fan since I was inside the car when I heard the noise.
correct me if I am wrong but when you turn off the car the only thing still spinning is one of the fan or both? I dont think this has to do with belts?

 

If it was kinda warm out yesterday and you driving around for a while your fan prolly comes on.....The fans come on when they want...Thats why they say keep your hands away from em when you are workin on your car because they turn on when the car is hot.

 

Wouldnt it just be a belt screeching?

 

no dont think so, it sound like when a fan is spinning and when is coming to a stop something is touching. I dont think is the belt because when u turn the car off the belt immediately stop righ? the noise last for about 3 seconds after the car is off.

 

maybe your shroud is loose for one of the fans making the sound. i think the radiator fan comes on whenever it needs to, its not dependent upon the engine being on. i think u have to turn the ac on to run the ac fan or at least the blower on? the radiator has the bigger fan. when the radiator ages it gets loose and vibrates along its support. bad motor mounts can make the support loose also.

 

hey guys I just want to update you.

today I took my car to the shop and we found out the fan is touching this metal that is righ in front of the fan. the fan to cool down the engine.

A few days ago I hit the floor (thanks to the streets here in nyc) and somehow I hit it so hard that the metal under the car push this other metal that is in front of the fans even closer to the fans and now the fan is touching it and the solution is to take to a body shop so they can pull this thing.
and while looking at this problem under the car we notice I also hit the transmission very hard and now there is some type of oil coming from the seal. heh

 

glad u found the source of the noise. that's terrible about the oil leak. is it oil as in rear main engine seal or an actual transmission seal? good luck.

 

is the seal between the engine and the transmission.
my mechanic was nice enough not to charge me for the 2hrs we spend finding the problem but I did give him $40 tip. Now I need to find the time and get it fix.