Underbody "flapping" noise at 50+mph

[mfc1337]

Hi all,

New owner of a "new to me" 2018 Stinger GT1 AWD. Car has been great, but it's got a noise that I unfortunately didn't notice until after I bought the car. It sounds like a flapping noise somewhere under the engine/transmission area when the car goes over about 50mph. I suspect it has to do with one of the underbody shrouds/deflectors. I took a peak underneath, all the bolts holding the front and rear shrouds are there and tight but it is missing the circular oil filter access cover. Do you think the filter access hole being uncovered could cause the shroud to flap from the air at speed?

Thanks

 

[G70LEbyAdoom]

Hi all,

New owner of a "new to me" 2018 Stinger GT1 AWD. Car has been great, but it's got a noise that I unfortunately didn't notice until after I bought the car. It sounds like a flapping noise somewhere under the engine/transmission area when the car goes over about 50mph. I suspect it has to do with one of the underbody shrouds/deflectors. I took a peak underneath, all the bolts holding the front and rear shrouds are there and tight but it is missing the circular oil filter access cover. Do you think the filter access hole being uncovered could cause the shroud to flap from the air at speed?

Thanks

Yes, it could. that hole is large enough to catch air.

 

[Aarvix]

I would fab up a replacement from something waterproof, you don't want that underbody panel flapping at speed. Even a little bit of a gap could be enough for it to catch enough air to rip off. A new air dam is nearly $300, ask me how I know...

What did you do to your Kia Stinger today?

 

[mfc1337]

I would fab up a replacement from something waterproof, you don't want that underbody panel flapping at speed. Even a little bit of a gap could be enough for it to catch enough air to rip off. A new air dam is nearly $300, ask me how I know...

Yeah fabbing something up temporary is probably a good idea. I do have the replacement access cover on order, but who knows how long it will take to ship.

 

[MerlintheMad]

Welcome to the Forum. And I'll add a third vote for getting that gaping hole plugged pronto before you go fast enough to cause fasteners failure.

 

[mfc1337]

So quick update on this. I really thought it was one of the underbody panels but definitely not the case. I was able to put the car up on a friend's lift and made sure they were all fastened tightly. The noise has started to get more severe and actually feels like something with some weight to it oscillating up and down and hitting the floor. You can actually feel it through the pass side floor or resting your hand on the center console/shifter. I'm suspecting it's driveline related, maybe a driveshaft/carrier bearing issue. Strange for that to happen on a car with 11k miles, but it's at the dealer now so hopefully I'll find out more soon.

 

[rpoffen]

So quick update on this. I really thought it was one of the underbody panels but definitely not the case. I was able to put the car up on a friend's lift and made sure they were all fastened tightly. The noise has started to get more severe and actually feels like something with some weight to it oscillating up and down and hitting the floor. You can actually feel it through the pass side floor or resting your hand on the center console/shifter. I'm suspecting it's driveline related, maybe a driveshaft/carrier bearing issue. Strange for that to happen on a car with 11k miles, but it's at the dealer now so hopefully I'll find out more soon.

IIRC, the front drive shaft on AWD passes by the passenger (right) side of the transmission.

 

[mfc1337]

Update part 2...So as I kept driving the car the problem was getting worse. I took it into Carmax for them to look at (barely made it there as the vibration/noise was getting very severe over 50mph). Carmax sent the car out to a Kia dealer who found it needed a new transfer case(!) They also said there was no ETA on parts availability so the car could be sitting for quite some time. Because I was still in the 30 day window I decided to return the car to Carmax.

I got lucky and found a white 2019 GT1 at a local dealership and just picked it up this weekend. A few more miles (11k vs 30k on this one), but the car is in better shape and there's a couple extra features the 2019s come with like ventilated seats and wireless phone charger. This was a giant PITA but in the end I think I ended up with a better car.

 

[General_Vodka]

Update part 2...So as I kept driving the car the problem was getting worse. I took it into Carmax for them to look at (barely made it there as the vibration/noise was getting very severe over 50mph). Carmax sent the car out to a Kia dealer who found it needed a new transfer case(!) They also said there was no ETA on parts availability so the car could be sitting for quite some time. Because I was still in the 30 day window I decided to return the car to Carmax.

I got lucky and found a white 2019 GT1 at a local dealership and just picked it up this weekend. A few more miles (11k vs 30k on this one), but the car is in better shape and there's a couple extra features the 2019s come with like ventilated seats and wireless phone charger. This was a giant PITA but in the end I think I ended up with a better car.

Wow who would've thought.... Glad you were still in the return period. That's crazy that the transfer case was actually the issue. Did kia ever tell you why it went bad?

 

[mfc1337]

Wow who would've thought.... Glad you were still in the return period. That's crazy that the transfer case was actually the issue. Did kia ever tell you why it went bad?

Sadly never got the root cause from Kia. This isn't a common issue so I'm thinking abuse by previous owner. Maybe it was a brake snip car, or just beat to death?

 

[General_Vodka]

Sadly never got the root cause from Kia. This isn't a common issue so I'm thinking abuse by previous owner. Maybe it was a brake snip car, or just beat to death?

I'm pretty sure brake snip causes the tq converter to fail. Could be anything though

 

[MerlintheMad]

Carmax sent the car out to a Kia dealer who found it needed a new transfer case(!)

That fits your subsequent observation of feeling it through the floor on the passenger side. Glad that you have a better Stinger now.