Hood flutter above 65 MPH

[judgefudge72]

Update 4/27: approved for a new hood from ford.

I’ve searched for this topic and saw some older threads discussing it but no real solutions.

4dr big bend mid 2.3 non sas. I get significant hood flutter(up and down movement) at freeway speeds. Usually starts around 65 mph and gets much worse around 75. Seems to get increase in intensity if there is a crosswind or if I’m behind or next to a semi. I had a 2020 Tacoma that did this but only a little bit. I’d estimate the bronco has almost half an inch of up and down movement/ flex in the hood at its worse.

All the foam in between the honeycomb and hood skin seems to be in tact. I’ve tried adjusting the hood stops to get a better seal out of the front seal but it didn’t help. Added some 3/16” fuel line in the void between the hood and the front seal and that seemed to help a bit. I’m at about 2700 miles and it’s been there since day 1.

Any ideas? My next step is talking to my dealer about it. Wondering if adding the sound deadening found on high and lux trims would help at all.

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[4xFord]

I was having the same issue. My heart stopped everytime it started fluttering as I second guessed my hood closing ability.

Fortunately I had some 3/4" backer rod around the house and stuffing it into the gaps (missed by factory foam) seems to have fixed it.

I wasn't sure how it would hold up to engine heat but 1,500 miles later it is holding up. I would also caution against stuffing foam at the very front and rear of the hood because of some larger voids. Work from the middle of the honeycomb out.

 

[judgefudge72]

I was having the same issue. My heart stopped everytime it started fluttering as I second guessed my hood closing ability.

Fortunately I had some 3/4" backer rod around the house and stuffing it into the gaps (missed by factory foam) seems to have fixed it.

I wasn't sure how it would hold up to engine heat but 1,500 miles later it is holding up. I would also caution against stuffing foam at the very front and rear of the hood because of some larger voids. Work from the middle of the honeycomb out.

Thanks, gonna order some up and give that a shot. I can really only see the flex in the middle just before the hump/bulge.

 

[mybikeisred]

Haven’t noticed this at all in my Bronco, but I used to have a Saleen Mustang, and it always scared the shit outta me once I got above 110-120. Looked like waves on the ocean, felt like the hood might come flying off the car at any second.

 

[judgefudge72]

I was having the same issue. My heart stopped everytime it started fluttering as I second guessed my hood closing ability.

Fortunately I had some 3/4" backer rod around the house and stuffing it into the gaps (missed by factory foam) seems to have fixed it.

I wasn't sure how it would hold up to engine heat but 1,500 miles later it is holding up. I would also caution against stuffing foam at the very front and rear of the hood because of some larger voids. Work from the middle of the honeycomb out.

So I got this stuff in and put it in as many places as I could. It was pretty difficult to work into the honeycomb. I didn’t notice much improvement and when I checked the next day most pieces were loose so I took some out that weren’t doing anything and doubled up some other spots.

How much did you put in the framework on yours? How long of pieces?

Also while I was under there I noticed several spots where the factory foam was no longer attached to both the hood skin and framework. Wondering if that could be the cause of my issue right there.

 

[4xFord]

I confirmed that it's 3/4". I had some pieces doubled over that might have been 10" but most of it was shorter.

I haven't had anything come loose, the ends are all tucked in and it fits snug. The backer rod I had was contractor grade, for concrete joints, and will only compress ~50%.

I didn't notice any separation so you may be on to something there.

 

[Monster1926]

Military grade aluminum. Mine has it slightly also.

 

[PSUTE]

Have not experienced it, and I routinely drive 75-80 on the freeway...

 

[judgefudge72]

Here are some pics of the separated foam in question. These are all near the middle of the hood where it flexes the most.

 

[judgefudge72]

Just thought I’d post an update. I’ve experimented with the backing rod in several spots and haven’t noticed a difference. The hood seal with fuel line behind it doesn’t make a difference for the flutter but it did take care of a strong whistle I had coming from the front. I have some dash cam videos I can post but the angle doesn’t show off the flutter very well. Seems to be affected by cross winds the most. I can go 70+ on a calm day and it barely moves.

I’ve made an appointment to drop it off with the dealer I bought it from to see what they think. Unfortunately that’s two weeks away and they said they would most likely need it for a whole day.

 

[akturbo]

Add me to the list. Very noticeable flutter at 75MPH with wind, so bad I though the hood wasn't latched.

 

[judgefudge72]

Add me to the list. Very noticeable flutter at 75MPH with wind, so bad I though the hood wasn't latched.

On yours is it mainly in the middle in front of the hump/bulge but you can see the bulge moving up and down with it? I see you have lux, have you checked under the hood sound deadening to see how your foam looks?

Mine goes in on Thursday and I’m going out of my way to take it to the dealer I bought it from. They are going to have it for at least the day. I’ll keep the thread updated with what they say. I’m thinking that the two halves of the hood weren’t properly adhered. Also seems like it’s getting worse but I could just be focusing on it more.

 

[mdFord]

Could be a Ford thing, my 2020 Ranger does this at highway speeds. It's got an aftermarket grille so I just figured it was that (don't remember if it had it with the stock grille).

 

[BigMeatsBronco]

Hmm now I'm gonna go look under mine....I thought my plastic hood protector was causing this, but now I'm wondering if the hood isn't glued correctly?

 

[xusarmy]

Add me to the list. Very noticeable flutter at 75MPH with wind, so bad I though the hood wasn't latched.

Me too, I notice this often, feels like the hood isn't locked down.

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