Thunk in the trunk

[bluegenesisfl]

Re: Thunk in the trunk -Follow-up

I now have my Genesis back.

As it turns out torquing the rear suspension bolts to spec has NOT fixed the thunk in the trunk.

I still suspect the rear seat belt retractors.

My noise occurs at speeds under 30 MPH, is random, occurs sometimes on slight acceleration / deceleration, or going around low speed turns.

It is not a metallic sound. It sounds like a padded object sliding in the trunk and hitting the side. Sometimes louder than others.

If we had fold-down rear seats, I would suspect a rear seatback was not latched tight.

I'll keep looking and listening, and let you know if I find the answer.

 

[lobsenza]

Is anyone sitting in the back seat? Try buckling the rear seat belts without a passenger and see if it makes a difference. You could remove a seat belt retractor, but that would be a lot of work.

 

[Dezoris]

Our test car with the 5.0 did this often when usually taking off at first I thought it was wheel hop. No issue with the 3.8L, sounds like something in the trunk checked underneath nothing was loose.

 

[Alwaysforward]

Try with and without the rear shade up. Next try with and without the rear side window shades up. Just something you can rule out. Process of elimination.

 

[Midnightsun]

I have not experienced this at all with my AWD. Are there any here who have this who have AWD or is this only happening on the RWD models?

 

[bluegenesisfl]

Just to recap the steps I've taken so far to determine the source of the thunk in the trunk.

Removed everything from the trunk, everything!
-trunk mat
-tools and tool carrier
-spare tire and hold down

Checked the battery to be sure it was properly installed and tightly held down

Rear seat belts pulled and snapped closed

Rear arm rest pulled down

Arm rest trunk access door checked to be sure it was properly closed

BTW - thanks for the suggestion about the sunshades. I'll try that next.

I'm also considering pulling out the rear seat bottom, and seeing if that makes the sound easier to locate.

 

[BrazGenesis]

Fuel displacement in the tank?
Does it happen with full tank ?
No loose volumes in the spare surroundings?

 

[mcconh]

I have not experienced this at all with my AWD. Are there any here who have this who have AWD or is this only happening on the RWD models?

Canadian, 3.8 luxury, AWD, full tank of gas.
I had it happen once the first week I had the car when making a fairly slow right turn at a light. The THUNK, from the right rear seat area was loud. It has not happened again in the six weeks since that event.

 

[Midnightsun]

Canadian, 3.8 luxury, AWD, full tank of gas.
I had it happen once the first week I had the car when making a fairly slow right turn at a light. The THUNK, from the right rear seat area was loud. It has not happened again in the six weeks since that event.

OK, so we know it has nothing to do with rwd vs awd, thanks for the update.

 

[bluegenesisfl]

Okay, I tried it with the sunshades up and down. It makes no difference. We drove about 70 miles today, with some stop and go traffic. I heard it about 8-10 times.

The idea that it may be coming from the fuel tank area merits some checking. I will look into that.

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[Alwaysforward]

I recommend placing your cell phone on voice recorder and place in various locations (rear seat left, rear seat right, truck left, trunk right etc...) to help narrow down the location. Might help in finding what is causing this.

 

[bluegenesisfl]

Using the voice recorder on my iPhone is a good idea. This actually occurred to me, but I hadn't got around to trying it.

I contacted Hyundai Customer Care about the noise, and there is now involvement by Hyundai USA. A case number has been set up, and they are going to contact Red Hoagland Hyundai about doing further follow-up to try and locate the source of the sound.

BTW we did check the fuel tank, and it is properly installed and tight. However, there remains the possibility that perhaps it is the fuel level float bumping around.

We keep looking!

 

[jimb100]

I had mine in yesterday for the tail light recall and an oil change. Asked them to check the thunk.

They couldn't replicate the problem which didn't surprise me as sometimes I can't either. There's something there but it seems very difficult to get a handle on.

 

[bluegenesisfl]

Re: Thunk in the trunk - Update

I'm getting ready to leave on a 3000 mile trip. I will use this opportunity to try to localize the thunk.

When I return home I will head over to Red Hoagland, where we will pull the rear seat and drive the car around in an attempt to find out what is causing the sound.