Hood Flutter Investigated and Corrected

[Zach993]

Exhaust buzzzzz, could be turbo whine coming through.. is it at the tailpipe?

Not me. I don’t have any buzz

 

[okcG24]

Exhaust buzzzzz, could be turbo whine coming through.. is it at the tailpipe?

It's definitely rear driver side area, only at low rpm (not sitting at idle) and more prevalent in Comfort and Eco. Maybe the other settings keep the rpm's a little higher so not as noticeable. Very hard to explain but numerous people riding on back seat have been like "what is that buzzing sound?". It's not license plate or trunk vibration nor is it anything loose in the exhaust. I may just have a shop cut and replace the rear resonator and hope it fixes it. Or, I may just disconnect the rear exhaust section right in front of rear axle and drive it a bit to see if I can isolate the issue to that rear resonator. Wouldn't be the first buzzy resonator.

 

[Toxicdog]

It's definitely rear driver side area, only at low rpm (not sitting at idle) and more prevalent in Comfort and Eco. Maybe the other settings keep the rpm's a little higher so not as noticeable. Very hard to explain but numerous people riding on back seat have been like "what is that buzzing sound?". It's not license plate or trunk vibration nor is it anything loose in the exhaust. I may just have a shop cut and replace the rear resonator and hope it fixes it. Or, I may just disconnect the rear exhaust section right in front of rear axle and drive it a bit to see if I can isolate the issue to that rear resonator. Wouldn't be the first buzzy resonator.

I had a slightly bent heat shield causing a buzz around the rear axle. Could be something similar?

 

[okcG24]

I had a slightly bent heat shield causing a buzz around the rear axle. Could be something similar?

I'll inspect it again. Thanks!

 

[ggils2324]

Amazon.com

Has anyone tried this???

 

[Motown]

I'm not fully caught up on the conversation regarding the hood flutter issue, but I took my OT in for the 5k freebie service and asked them about the issue. I've noticed it since day 1 but it's not something that really bothers me; but regardless, I brought up the issue with the service rep at my Lexus dealer (Greenville, SC).

They informed me that they do have a fix for the hood flutter issue, however it would require that the car goes to a body shop. They didn't give me any exact details about what that fix at the body shop entails. Hope this helps shed some light on the issue!

 

[R!ck]

I'm not fully caught up on the conversation regarding the hood flutter issue, but I took my OT in for the 5k freebie service and asked them about the issue. I've noticed it since day 1 but it's not something that really bothers me; but regardless, I brought up the issue with the service rep at my Lexus dealer (Greenville, SC).

They informed me that they do have a fix for the hood flutter issue, however it would require that the car goes to a body shop. They didn't give me any exact details about what that fix at the body shop entails. Hope this helps shed some light on the issue!

Just WOW!

 

[UTHORNS76]

Just WOW!

Whatever it takes, Lexus should just own up to the problem and fix it under warranty.

 

[Bluegill]

Just picked up my GX from Bell Lexus here in Scottsdale, Arizona. I took it in a couple days ago to have the front brakes replaced to cure the squeal. While I was talking to the Service Consultant, I asked if they had a solution yet for the hood flutter. He didn't know anything about it but he typed it up on my service order. The guys in the Lexus shop knew all about it and they sent my truck over to a body shop where they squeezed in a bunch more adhesive to settle down the hood (it's the white stuff in the photos below). I hit 90 mph on the short highway run home from the dealer and the hood flutter is very much improved. There is still a bit of movement but not nearly what it was before. Previously, it was like a flag waving in the wind.

So that's that. I'll re-install the fabric & cardboard panel now and call this one done.

 

[vraa]

Just picked up my GX from Bell Lexus here in Scottsdale, Arizona. I took it in a couple days ago to have the front brakes replaced to cure the squeal. While I was talking to the Service Consultant, I asked if they had a solution yet for the hood flutter. He didn't know anything about it but he typed it up on my service order. The guys in the Lexus shop knew all about it and they sent my truck over to a body shop where they squeezed in a bunch more adhesive to settle down the hood (it's the white stuff in the photos below). I hit 90 mph on the short highway run home from the dealer and the hood flutter is very much improved. There is still a bit of movement but not nearly what it was before. Previously, it was like a flag waving in the wind.

So that's that. I'll re-install the fabric & cardboard panel now and call this one done.

View attachment 7625View attachment 7626View attachment 7627View attachment 7628View attachment 7629

Thank you for sharing these pictures, very informative

 

[Zaki6]

Just picked up my GX from Bell Lexus here in Scottsdale, Arizona. I took it in a couple days ago to have the front brakes replaced to cure the squeal. While I was talking to the Service Consultant, I asked if they had a solution yet for the hood flutter. He didn't know anything about it but he typed it up on my service order. The guys in the Lexus shop knew all about it and they sent my truck over to a body shop where they squeezed in a bunch more adhesive to settle down the hood (it's the white stuff in the photos below). I hit 90 mph on the short highway run home from the dealer and the hood flutter is very much improved. There is still a bit of movement but not nearly what it was before. Previously, it was like a flag waving in the wind.

So that's that. I'll re-install the fabric & cardboard panel now and call this one done.

View attachment 7625View attachment 7626View attachment 7627View attachment 7628View attachment 7629

That is good to know!
Do you happen to know the name of the particular adhesive they used?
Some of us may need to take it to the dealer/body shop and ask for it specifically when showing these pictures.
Thanks!

 

[Bluegill]

I have no idea and it's not on the paperwork. Lexus took it to their preferred local body shop - they don't do body work at this dealership. I can certainly ask, though. It's white goop that's still a bit soft to the touch.

 

[Zaki6]

I have no idea and it's not on the paperwork. Lexus took it to their preferred local body shop - they don't do body work at this dealership. I can certainly ask, though. It's white goop that's still a bit soft to the touch.

Sounds good.

AI tells us the following:

To stop hood flutter, an "anti-flutter adhesive" is typically used, with brands like SikaSeal being a popular choice in the automotive industry; this type of adhesive is specifically designed to bond the inner and outer panels of a hood, effectively dampening vibrations and preventing flutter.

Key points about anti-flutter adhesives:

• Function:
  They create a strong bond between the hood's inner and outer panels, reducing the space for vibration and minimizing flutter.
  
  
• Application:
  Usually applied as a bead or dot pattern along the seam where the panels meet.
  
  
• Material properties:
  Often rubber-based or vinyl plastisol, providing both adhesion and vibration damping qualities.

 

[Bluegill]

Ah, plastisol. I worked with that at a manufacturing plant back in high school in the mid-1980s.

We used it to coat the inner lid ring on adjustable manhole riser devices. The coating dampened vibrations from traffic driving over the manhole lids.

I knew that summer job would prepare me for my future life!

 

[JD.]

OK, the little replacement clips for the black under-hood mouse fur "insulation layer" arrived so I popped out all the factory clips with a body panel clip pulling tool. They break upon removal, not the re-usable type. The black panel is just for show, paper-thin, backed with cheapo fiberboard about as thick as a human hair.

Here is the Amazon page for the clips - $10 for 25 pieces, you need 10...always good to get extras:

Amazon.com

So, the underside of the hood panel is actually highly-engineered. Lots of structural bends, air flow slots, etc. On the topside of the hood, the outer wheel-location humps over the fenders have bends that obviously define the fenders. These major bends on each side give it plenty of rigidity in this area. Furthermore, there are little rubbery plugs that wedge between the low sides of the fender bends and the inner hood structural panel, which supports this bend line from below. See the pics below.

The problem is apparent: the topside expanse in the middle of the hood appears to be completely unconnected to, and unsupported by, the underside structural panel. Coincidentally, this is the part that flutters at highway speeds. This topside expanse is about 40" wide across the hood.

It looks like sound deadening paneling (butyl or foam padding) is not going to work because you can't apply it directly to the underside of the topside, if you see what I mean. The inner underside structural panel is in the way.

I'm thinking that some rubber spacers stuck in there (like the factory rubbery plugs already installed under the bends) would do the trick to form a wedge between the inner structural panel and the topside expanse. Or, maybe even easier, would be to spray some heat-resistant expanding foam up in the little cutouts all across the expanse. I wonder if this would bulge the hood? Probably not if you let it just expand freely and ooze out the little cutouts and the sides, then trim it clean. Would really suck to bulge your hood trying to fix a flutter...LOL. Maybe just stuff some thermal batting up in there?

Opinions? Neoprene gasket material comes in a variety of thickness, lengths & widths. It might be exactly what you need.

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Amazon.com