This is me walking from the driver's side of my car to the front. The car is on an incline facing down and the hood is open. A second person is holding the brake and revving the engine to about 1500 RPM.

There's a high-pitched overtone to the normal engine sound. It sounds like a metallicized version of rushing air.

Here are my notes on it:

a. Very loud and obvious from outside the car, somewhat audible inside.
b. Appears from roughly 1300 RPM – 2500 RPM.
c. Occurs quite often, almost exclusively at the start of a trip.
d. Duplicated by holding 1500 RPM in reverse on a steep hills (e.g., a driveway). This happens constantly: I visit a house with steep driveway, and almost every time I back out, this noise begins.
e. Once it starts (from the incline), it continues to occur on flat ground in Reverse or Drive when the brake is held and the RPM is above 1300.
f. The overtone has also occurred going forward on flat ground for the first 20 MPH or so with moderate pedal pressure.
g. Does not occur in neutral.
h. Usually stops during the course of a trip

Can you guys help me figure out what this is? It appeared about 5000 miles ago.

Also, a mechanic told me that the idle noise suggests the car may need valve adjustment. It has about 40K miles. You can hear the idle in the last five seconds of video. Is he right?

Thanks!

 

😁sounds like you need to take it in . Sounds like a combo of valve train noises and bottom end noises .

 

That does not sound good to me.

 

I'm definitely bringing up both things at the next oil change. I'm not sure what 'normal' valve noise is though, and that's what they'll inevitably say. "Oh, it's fine." Is it?

 

Tell them to tell or show you what the normal spec is for the oil pressure on a gauge and nissan spec sheet and you should be good .

 

I'm not concerned with the high pitched tapping but am with the lower toned knock.

 

Take the oil pan off and inspect for damage and put a magnet on the oil pan and see if it collects metal bear in pieces and take it to the dealer you might have the extended power train warranty that we all have now because of so many recalls on short and long blocks and cvt's .