Idle Noises

unwrittenLaw

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2015 BMW 335i Sedan / 2015 Nissan Pathfinder Platinum 4WD
When the MSP engine is idle, I noticed that every 30 seconds or so a reving-type sound happens for a bit than it stops...is this normal? And since I added the K&N air filter when this happens, is seems like the exhaust shakes and vibrates the car a little...any idea of whats going on..?

Thanks
 
after driving i sit in the car and wait 30-45 secs. when you bought the car, didn't they tell you that you have to let the turbo cool down? but yeh, i get the same thing. sounds like a fan spinning loud or something. i'm pretty sure it's normal.
 
It is the cooling fan, when you put the K&M on it sits right behind the left front fan. The turbulence from the fan causes the intake air to be uneven. This is why I extended my K&N into a heat shield box where the overflow bottle used to be. I addressed this on my website at www.geocities.com/kiva75 look at the CAI#2 to see the heat shield.

I know the 5.0 Mustangs had this same problem with the K&N filters without a shield. Technically the car stays cool at speed and the fan typically does not turn on when you are driving, only at idle. This may be a different story during the summer.

Britt
 
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