hayzai

So I just got my car back after my first oil change.. Didn't notice this sound after a little bit of driving.

Basically it's a slightly higher pitched 'whining' / humming in the cabin of the car that I've never heard before and it's louder and more high pitched the higher the rpm of the engine.. Has nothing to do with the speed of the car because I can even hear it slightly when the car is idling.. It starts becoming really noticeable around 2.5 to 3k
Never noticed this sound before the oil change and it almost sounds like more of the sound is coming through from the engine bay to the cabin..
Anybody have an idea what this might be??
Thanks!

C7&7

Post a video? Make sure the car isn't too full of oil. Start it and let it warm up for like 5 min then kill it and check the oil level. If it's past half way on the "hot" area it's too full. Not saying that would cause a humming noise but it's gonna cause other issues. Who did the oil change?

hayzai

I will try and get a video today if I get the chance...
When I drove yesterday I kept an eye on the oil pressure and temperature and I didn't see anything out of the ordinary with them ( ~ 40 psi and like a few ticks under 220 F )

I had it done at a Chevy dealer

C7&7

Ok. Cool a video will help.

The pressure won't indicate too much oil on a dry sump car. I'd really let it warm up and check the oil level with the engine off after its warm. If it's past half way up the hot area they overfilled it. The book said 10.3 quarts in early 2014 then changed to 9.8...I run 9.25 in mine. Overfilling the oil is a nasty situation. Especially without a catch can.

hayzai

So I checked the oil when it was warm.. seems to be 40% of the way up the hot area so there's that...

I took two videos

Video 1 :

In this video the sound might be a little easier to hear.. After the revs drop if you pay attention you'll hear this humming ( which was never there before the oil change )

Video 2 :
https://www.youtube.com/watch?v=cBfr...ature=youtu.be

This one is just a video of the car idling.. again if you pay close attention you'll notice the humming

Might want to turn up the volume to hear it because it's so faint and probably not too noticeable.. but it's there

C7&7

Man I am not noticing a humming sound. Sounds fine to me...

C7&7

Does it change with the AC on or off? It's not the coolant fans is it?

hayzai

Nope! The videos were taken with AC off.. and it's definitely with the RPM..
I don't know it's just a sound I never noticed before and maybe it's suddenly a lot louder than it was?
I am almost certain it wasn't there before the oil change though :/

hayzai

After the second rev it begins at around 8 seconds.. Like you hear that besides the exhaust there's this humming in the background that's slowly dropping as well.. Not sure if I'm making any sense here..

Wormwood

I hear the humming in that video, ask the dealer if they completed any bulletins, communiques, technical service recalls, anything besides changing the oil...

Also, how long did the dealer have the car? We're you there at the dealership the whole time?

I'm guessing maybe the technician put the wrong kind of oil in the vehicle.

To me it sounds like a gear pump is laboring... I dunno, but it doesn't sound right.

reminds me of the sound a steering pump will make when you load them up...

Wormwood

hayzai

They've had it for one day, but I will be back by the end of this coming week so I will ask them some questions..

hayzai

Just confirmed with a friend that the sound exists and seems to be coming from under the passenger side near the front..

Wormwood

Maybe a scavenge pump.... Or some sort of pump can't reprime itself? A partial Blockage of some sort?

hayzai

Dropped it off at the dealership and fortunately they could duplicate the sound so they're looking into it.. Will let you guys know if they figure out where it's coming from!

hayzai

So this was the message I got from the rep..

TODAY WE DUPLICATED THE NOISE FROM THE DRY SUMP OIL SYSTEM ON 2 SIMILAR Z51 PACKAGED 2015 CORVETTES, THE NOISE IS LOUDER IN 1 VEHICLE THAT HAS NOT HAD THE OIL CHANGED AS OF YET (DUE TO LOW MILEAGE) THEW OTHER CAR HAS THE SAME SOUND AS YOURS AND ABOUT THE SAME NOISE VOLUME, AT THIS TIME THE NOISE IS CONSIDERED A NORMAL CHARACTERISTIC OF THE VEHICLE AS THERE IS NO PUBLISHED INFORMATION REGARDING IT, CLEARLY THE NOISE WAS THERE IN YOUR CAR,NOTHING BUT A OIL CHANGE WAS DONE, NOTHING OUT OF PLACE,LOOSE OR OTHERWISE

Thoughts?

spearfish25

raising the dead here but my Z06 is doing this. First noticed it when starting the car cold. But after my recent oil change its more noticeable around 2-3k RPM. Weird.

hayzai

woah good to know my post from that long ago is benefiting somebody else ( kind of )

Sort of an update :
Every single time I get an oil change it gets louder, then it just becomes less noticeable until I get an oil change, and the cycle repeats.
Engine is currently at ~23k miles and no issues whatsoever! So it shouldn't be an issue
On a side note I think I might have another issue with the car that I'll be posting about soon..

spearfish25

Glad to hear it seems like a nonissue. Like I said, I had a very similar sound and rpm dependent behavior with fluid running through oil lines in a 370Z. The sound does seem near the dry sump so I'm thinking it's the oil flow as well. I'll pay attention to see if it quiets down with time after the oil change.

Tow

I had this issue also on my brand new Grand Sport it was determined to also be the dry sump system causing the sound. For me it had more of an exhaust drone sound. This lasted for about 5-600 miles now I just don't hear it anymore.