Under Hood Coating

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fish
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Under Hood Coating

Post by fish » Tue Mar 26, 2019 4:37 pm

Hey guys--

Has anybody reapplied the underhood texture coating after removing the old stuff? I contemplated just leaving it without the coating, but it looks like it'd be useful for protecting the outside paint from some of the engine heat as well as knocking down some of the panel noise, so I'm thinking I ought to put something on to replace the factory coating. The OEM coating looks vaguely like the stuff that's inside the doors, too, so it might be a two-fer (although I'm leaning toward some of the 3M NVH products for the doors).

I've looked at the 3M and Wurth rocker shutz/undercoat products, and they're good stuff, but it doesn't look like the texture finish is the same as OEM and I'm not sure how happy those would be with constant exposure to engine heat. Anybody have any success with a specific product?

--Scott

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Re: Under Hood Coating

Post by C.Costine » Tue Mar 26, 2019 8:32 pm

I don't remember what I used but it was an aerosol can. It came out pretty good, I found that you need to hold the can at an angle to the surface in order for it to build up any thickness. I used two cans. I think that with nothing it would be tinny and rattly. If I were doing it over though I would use Lizard Skin and get a thicker more OEM looking coating.
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Re: Under Hood Coating

Post by Linda » Tue Mar 26, 2019 8:48 pm

What about using an under hood insulation? Easier to work with and changing it out is easier also, it seems to me. I saw one that was designed to melt the clips in a fire and then fall to help smother it. Something like this:
https://www.carid.com/articles/hood-ins ... touch.html

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Re: Under Hood Coating

Post by bakerjf » Tue Mar 26, 2019 9:44 pm

When/if I have to do it again I’ll use Line-X, and then paint it the body color.
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Re: Under Hood Coating

Post by bobd » Wed Mar 27, 2019 5:28 am

I used truck bed liner and then painted it body color.

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Re: Under Hood Coating

Post by GeoffM » Wed Mar 27, 2019 10:38 am

If I recall correctly, one of the long-time roadster guys told me that under-hood coating was not OEM. I'd be surprised though, as almost every car I've seen has it.
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Re: Under Hood Coating

Post by 68DSU » Wed Mar 27, 2019 10:44 am

I recall having an uncoated hood. It may have been a replacement after an encounter with another car in the 70's. I coated it partly to give it a little more strength to resist the oil can effect. I used a spray on underseal but there are plenty of better products on the market now.
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Re: Under Hood Coating

Post by spl310 » Wed Mar 27, 2019 11:16 am

I am certain that many roadsters had that stuff. Very early and very late cars may not have. Replacement hoods didn't iirc
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fish
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Re: Under Hood Coating

Post by fish » Wed Mar 27, 2019 12:44 pm

I'm pretty sure it was an OEM coating; the same stuff is inside the doors and rear quarters (behind the vinyl panels) on both of my cars. I like the idea of using the polyurea bed liner or one of the 3M products, but just wasn't sure how well they'd respond to engine heat. I may shoot a couple test panels and stick them under the hood on the '66 and drive that around a little to see how it does. It's entirely possible that I'm overthinking this, too. :-)

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Re: Under Hood Coating

Post by SLOroadster » Wed Mar 27, 2019 2:21 pm

C.Costine wrote:
Tue Mar 26, 2019 8:32 pm
... I think that with nothing it would be tinny and rattly. If I were doing it over though I would use Lizard Skin and get a thicker more OEM looking coating.
Nope, I scraped all that stuff off when I painted my car and it made zero difference in sound. It did take about a pound off the car however.

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Re: Under Hood Coating

Post by jrusso07 » Wed Mar 27, 2019 5:50 pm

You can use the clear coat chip gaurd usually applied to rocker panels. I used it in a z car under hood (and rockers). I don’t remember the product brand or name. It has to be reduced and sprayed...
Last edited by jrusso07 on Thu Mar 28, 2019 6:39 am, edited 1 time in total.
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Re: Under Hood Coating

Post by datsunrides » Wed Mar 27, 2019 8:34 pm

I use Dynatron Dyna-Pro undercoating under the hood on all my restorations. Can be topcoated after it dries. I like it because it hides all the little imperfections without the need to spend hours doing it the traditional way.
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