Hood Flex/Vibration Solutions

bennettlo · Saturday at 8:40 PM

Has anyone come up with a way to reduce the hood flex at highway speed? I added CLD (dynamat-like materials) to my doors which reduces flex in door panels. But I don’t see a way to do that with the outer hood skin because it’s not very accessible like the doors.

Here’s a photo I borrowed from the Internet. Those slits in the inner hood skin are pretty small and not that close to the front where I think I see flex.

D-mac · Saturday at 9:01 PM

I installed the ResoNix hood liner and it seems to take care of 90% of the flutter. Other CLD manufacturers make similar products.

bennettlo · Saturday at 9:30 PM

D-mac said:
I installed the ResoNix hood liner and it seems to take care of 90% of the flutter. Other CLD manufacturers make similar products.

Thanks for the quick reply!

Is this the one you used? ResoNix Fiber Mat Silver - Car Hood Liner & Sound Absorber

Did you notice sound benefits too?

Bad1975 · Saturday at 11:21 PM

There is a TSB for that, it was corrected on 25 model years.

The TSB has a bunch of solid core foam pieces installed and has an expanding bonding agent that gets applied to various locations in the size of a quarter. Lots of warnings about getting the expanding stuff of the correct size or it will dimple the hood. Looked like a pretty daunting task for the technicians to perform. I think it also highly recommended performing test applications for practice before applying to the customers hood. IIRC is was like 30+ locations to add the required hood stiffening to prevent the flutter.

Sorry I should have downloaded it but did not as it wasn't applicable to mine.

EOD Guy · Saturday at 11:25 PM

D-mac · Sunday at 12:29 AM

bennettlo said:
Thanks for the quick reply!

Is this the one you used? ResoNix Fiber Mat Silver - Car Hood Liner & Sound Absorber

Did you notice sound benefits too?

Yes that is a ResoNix hood liner, do not know if exactly the same. I’m not sure about the sound level reduction, would need a good microphone/software to verify. I believe it did lower front end body vibration.

shwazz714 · Sunday at 10:23 AM

Bad1975 said:
There is a TSB for that, it was corrected on 25 model years.

The TSB has a bunch of solid core foam pieces installed and has an expanding bonding agent that gets applied to various locations in the size of a quarter. Lots of warnings about getting the expanding stuff of the correct size or it will dimple the hood. Looked like a pretty daunting task for the technicians to perform. I think it also highly recommended performing test applications for practice before applying to the customers hood. IIRC is was like 30+ locations to add the required hood stiffening to prevent the flutter.

Sorry I should have downloaded it but did not as it wasn't applicable to mine.

Has anyone gotten the tsb done to their vehicle? Curious what it looks like to get it done - just mention good flutter to service department?

Bad1975 · Sunday at 8:16 PM

I guess I did save it, but its from Lexus. Not sure if Toyota ever released one?

Pavman2473 · Monday at 11:57 AM

D-mac said:
I installed the ResoNix hood liner and it seems to take care of 90% of the flutter. Other CLD manufacturers make similar products.

Was it easy to install. Do you
know if there are videos on installing this to the hood? Thanks in advance.

bennettlo · Monday at 2:15 PM

Pavman2473 said:
Was it easy to install. Do you
know if there are videos on installing this to the hood? Thanks in advance.

I haven't done the hood, but I just installed NVX deadener in my doors this past weekend. None of it is technically difficult, just time consuming. The doors involve removing the door panels and unplugging a number of electronics. The hood involves popping the clips off of the insulator (item 5 in EODGuy's pic above) which is not difficult. You cut the materials to size, peel away the backer and press it onto the metal or (in this Resonix example) the insulator panel attached to the inside of your hood.

The issue I see is that you'd really only be applying deadener to the Inner skin of the hood or the insulator panel. The hood (and the doors) have Outer and Inner metal skins. The flex and vibration on the Outer skin is what you see flexing while driving and adds to the overall noise you hear. I'm a little skeptical that material added to the Inner skin or insulator panel will help with vibration on the Outer skin.

All that said, beefing up the insulator panel must have sound deadening effects. The doors made a significant difference in reducing a lot of high-pitched noise at highway speeds.