1970s 1974 Eldorado hood oil-canning

[Cadman-iac]

I believe that is what happened. Hiw can I resolve this? Would expanding can foam for insulation work to fill in the gaps?

 The problem with the expanding foam is number one, it doesn't "grip" or bond to the steel like it should and will eventually come loose. Number two, is because it expands it can possibly push the hood away from the reinforcement structure distorting the skin to where you can see waves in it.
 The correct product to use would be a panel bonding agent of some sort that doesn't expand, but bonds to the steel.
   Your local paint and body supply store or a body shop can recommend the best one for this. I haven't done anything of this nature for decades, so my knowledge of what is available now is limited.

  Rick

[danjarrett1]

Thank you Rick...I did speak to a body shop today about that. I might let them just do it

[The Tassie Devil(le)]

I wouldn't use any expanding foam in case the expansion accidentally raised the hood skin higher in one spot, more than in others.   This would really show up in the surface undulations.

I would have a look at mine, but seeing as I have a new insulation pad, I would rather not attempt to remove it.

Surely someone out there could measure theirs to see what it is?   Plus, the trunk lid should also have the same material between the skins.

Many makers simply use a tarred felt layer between the panels, as when they get old, the parts not supported simply sag down and look awful.

Bruce.

[Cadman-iac]

  Dan,

There's probably about 20 different types of bonding agents or epoxies for the various body materials used in modern vehicles.
I remember that there was one that was recommended for the Pontiac Transport, Oldsmobile Silhouette,and the Chevrolet whatever it was, because they have a plastic skin over the metal framework of the body. The Pontiac Fiero was the same way.
On the hoods of the real cars from the 60's and 70's, the bonding agent is applied in small patches about half an inch to an inch in diameter depending upon where exactly it was used.
The one brand that comes to mind is 3M, they make all kinds of bonding agents. Steel to steel, aluminum, plastic, fiberglass, glass too I think.
The technology has changed so much since I was involved with a body shop back in the late 80's early 90's that if I need something like this now I'll have to ask the guys at the local paint supplier.
But like was mentioned earlier, the hood might have had someone sitting on it, which could have bent the reinforcement underneath the skin.
You would be money ahead to have a shop look at it for you before you do anything to it.
If you bond it yourself and you don't catch possible damage, you will cause yourself more headaches to fix that.
 I'm not saying don't do it yourself, but just be aware of the possible problems you may encounter.
 Good luck with your car.

Rick

[danjarrett1]

Thank you Rick. The sub gusset structure now not appear to be compromised by anyone sitting on the hood. There's just a consistent gap that I believe, if filled with the right sealant, would stop the hood vibrations in cruise. 3M is the best product I know of for bonding material together for sure

[TJ Hopland]

Do you see places where the structure is touching the main panel?  I will have to go look but I was thinking most places its touching.   

Anyone have a parts manual what years were the hoods the same?  I suppose that doesn't help since they could interchange even if they were trying some weight reduction design one year.

[danjarrett1]

I will try to attach a pic for your review. Several places where there is a gap between structure and the hood skin