kia stinger store

3.3TT Cavitation? noises over 4k rpm

98mystique2

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Before I set an appointment with the dealer and have them tell me that this is normal operation (it's not). I'm looking for anyone who might know where to tell them to start looking though searching has netted no results.

Somewhat long post of what I've troubleshooted thus far.
The car has a little over 3,000 mi on it right now it's done this ever since new. Initially I thought it was something like wastegate turbo noise but it does it even when off throttle and over ≈4,000 RPM.
From the driver's seat it sounded like it was coming from the passenger side but it may just be coming from somewhere in the dash center council or even outside the cabin.
the best way to describe the sound in person is similar to what cavitation sounds like in videos which is almost a rocks going through a pipe sound. Holding a constant speed at 55 mph and down shifting through the gears (see video 2) as soon as it gets above 4,000 RPM you get the noise. On throttle it makes the noise as well. It also makes the noises while in neutral and in park. It makes the noise regardless of whether the HVAC has the temperature maxed out/ minimum off/on recirc/fresh rear seat vent hot or cold. There is nothing in the glove box. Coolant levels look good engine oil was just changed and level is also good. It doesn't seem to matter if the engine is at operating time or before it reaches operating temp though I haven't completely tested that I guess. (Varying the temperature/vapor pressure should change cavitation point if it is that?)
I'm unable to pinpoint exactly where the noise is coming from with the hood open the engine noise drowns out my ability to hear it from the outside same as sticking my head under the car which makes me think it is in the dash?
I don't know enough about the hvac system flow to know if there is coolant flowing through the cabin/heater core at all times and if that could be the source or if it's transmission related or engine or none of the above.
I guess watch the videos and come up with your own hypothesis or guess.
 

vipeboy2000

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does it make those noises if you are parked/neutral and rev up past 4k? i'd start at heatshields, downpipe bolts, manifold bolts, look to see if anything is rubbing or close to rubbing subframes/exhaust.. I know some people with other makes have had strange rattles at very specific rpm's due to failed manifold gaskets..
 

cncBilly

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You got some weird :poop: going on there. Back to the dealer, let them figure it out. Is it totally stock?
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nhcowboy28

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oddball

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I would call that a rattle. See if any of the pipes around the firewall are loose. I'd pull the console trim and see if anything is loose in the center stack.
It's pretty subtle (by kia standards), so you might have to wrestle with the dealer for them to do anything about it.
 

SafetyPilotCal

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It's hard to decipher on video, but I think I'm in agreement that it's something rattling. I think you're hitting just the right frequency for whatever it is to really start moving. It almost sounds like really tiny gravel got stuck in the HVAC birdcage (where the blower motor is in) somewhere. That's really weird. If you close all the vents is it still as loud?
 

Aarvix

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sure sounds like cavitation to me. I'd think a rattle would be more consistent.

Gut says transmission pump, but hopefully it's something simple (and cheap to fix). I think a trip to the dealer is definitely warranted and I'd keep the RPMs low to be safe.
 

98mystique2

Newish Member
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sure sounds like cavitation to me. I'd think a rattle would be more consistent.

Gut says transmission pump, but hopefully it's something simple (and cheap to fix). I think a trip to the dealer is definitely warranted and I'd keep the RPMs low to be safe.
It has done it since new and I definitely have not lol. I'll take a look at the trans dipstick too, I hadn't yet but the thought crossed my mind for sure.
 
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