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#1 |
Registered User
Join Date: Oct 2015
Location: PNW
Posts: 3,587
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Hood insulation: Why? Do you keep it, or don't you?
I've had some vehicles with hood insulation and some without. From a high performance mindset, I can't see how it would help. Unless you live way up north in Coldlandia or Coldaska and have a hard time maintaining operating temperature, I don't see how there's a benefit except at initial startup/warmup. I can more easily make a case that it's there just to suppress sound. We all know that NVH is really important to the manufacturers. I would imagine that quiet seems smooth, and smooth + quiet probably help sell vehicles on test drives. Once up to operating temperature, it seems that any insulation would have a negative effect on performance. There is a lot of air going over the top of the hood that could draw heat out of the engine compartment. The closest thing to the hood is typically where the air and fuel are being drawn in. Any drop in temperature in that area sure seems like it would be a performance gain however minimal.
I'm considering pulling the hood insulation out of all of my rigs. I don't mind hearing the motor when it's doing its job. And generally speaking, if it's not revving up, then I don't think it's going to transmit much noise through the hood through the windshield and into the cabin. And I don't mind startling innocent bystanders and woodland creatures when I drive by. What do you guys think: Keep it, add it, toss it? Last edited by LT7A; 05-26-2018 at 01:12 AM. |
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#2 |
Registered User
Join Date: Dec 2014
Location: Euless, Texas
Posts: 511
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Re: Hood insulation: Why? Do you keep it, or don't you?
You are referring to the under side of the hood? I don't think it is necessarily insulation. From what I was told years ago, it is held up by plastic clips. Designed in the event of engine fire, clips will melt and it will fall down on engine to help smother fire.
I believe this is correct but someone else may know the original purpose if not for a fire.
__________________
1974 Cheyenne 10 LWB Stock 350 W/HEI /TH350/AC/4 BBL Quadrajet Mopar by Birth Chevy by Choice |
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#3 |
Post Whore
![]() ![]() Join Date: May 2015
Location: Alabama
Posts: 14,635
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Re: Hood insulation: Why? Do you keep it, or don't you?
^^^^never heard that before^^^^
Keith....what say you?
__________________
Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
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#4 |
Registered User
Join Date: Jun 2015
Location: West Hills California
Posts: 10
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Re: Hood insulation: Why? Do you keep it, or don't you?
Not that it has made a difference with the longevity of the paint on the hood of my truck, but that is the reason I have been told that all the Mfg started insulating under the hoods. I remember the plastic retainers were supposed to melt and drop the insulation, but I think that would just make it harder to put out any fire. If it in good condition, I would leave it. If its shredded up like the one in my truck, maybe say goodby.
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#5 |
Registered User
Join Date: Sep 2016
Location: Spokane, WA
Posts: 44
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Re: Hood insulation: Why? Do you keep it, or don't you?
I have always assumed it is for sound dampening, as it was included only in the more upscale trim packages.
I have never heard the fire suppression theory. I don't buy it. If that was the case it would seem that all trucks would have had it. As for the plastic retainers, they are just the most logical fastener for function and ease and speed of assembly. I do not have one on my pickup. I painted the underside of the hood so that it looks fine without it and the sound of the engine is pleasing to me. ![]() |
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#6 | |
Registered User
Join Date: Jun 2015
Location: West Hills California
Posts: 10
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Re: Hood insulation: Why? Do you keep it, or don't you?
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#7 |
Registered User
Join Date: Oct 2015
Location: PNW
Posts: 3,587
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Re: Hood insulation: Why? Do you keep it, or don't you?
Interesting! I had not thought of the fire suppression possibility. The only engine fire I've ever had to put out was low on the motor and feeding off of the accumulated oil leak build up. That was on the motorhome of somebody I didn't know along the highway. Curious, did the Cheyenne or Scottsdale trucks have hood insulation?
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#8 | |
Registered User
Join Date: Jun 2015
Location: West Hills California
Posts: 10
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Re: Hood insulation: Why? Do you keep it, or don't you?
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#9 | |
Registered User
Join Date: Sep 2016
Location: Spokane, WA
Posts: 44
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Re: Hood insulation: Why? Do you keep it, or don't you?
Quote:
https://gmheritagecenter.com/gm-heri...tion-kits.html You can look up your model year of pickup (or any other) and can read about how the different models were equipped. It is very well documented from the time the trucks were built. No guessing, conjecture or assumptions. |
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#10 | |
Registered User
Join Date: Jun 2015
Location: West Hills California
Posts: 10
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Re: Hood insulation: Why? Do you keep it, or don't you?
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#11 | |
Registered User
Join Date: Jan 2017
Location: wheaton IL
Posts: 659
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Re: Hood insulation: Why? Do you keep it, or don't you?
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#12 |
Registered User
Join Date: Jun 2008
Location: Moss Point,Ms.
Posts: 1,439
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Re: Hood insulation: Why? Do you keep it, or don't you?
I bought a new 80,C-20 Custom Deluxe and it didn't have the hood blanket.
The new 82,K-10 Silverado I bought has a hood blanket.(still have the truck) So,maybe it's a Silverado thing? And,I have had underhood fires with no damage to the paint,possibly because it has the blanket.Not big fires either. My 65 Impala has one and is held up with steel clips. Mike. ![]() |
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#13 |
Post Whore
![]() ![]() Join Date: May 2015
Location: Alabama
Posts: 14,635
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Re: Hood insulation: Why? Do you keep it, or don't you?
my 81 custom deluxe had it so its not just a silverado thang...
__________________
Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
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#14 |
Registered User
Join Date: Jul 2017
Location: Texas
Posts: 403
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Re: Hood insulation: Why? Do you keep it, or don't you?
My main concern, and the reason I keep mine, is sound deadening. Exhaust may sound cool, but engine noise is just annoying. Here's a better one I want to get someday:
https://www.amazon.com/FatMat-Hood-L.../dp/B00H6X4V7C |
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#15 |
Registered User
Join Date: Jun 2015
Location: West Hills California
Posts: 10
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Re: Hood insulation: Why? Do you keep it, or don't you?
Thank You for that link. When I get back to working on my truck, I will have some of that to replace what's already shredded, and all the little plastic retainers that have started to just fall away.
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#16 |
Post Whore
![]() ![]() Join Date: May 2015
Location: Alabama
Posts: 14,635
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Re: Hood insulation: Why? Do you keep it, or don't you?
I know mine came off ebay and I think this is where I got it...looks great,,, fit perfect.....https://www.ebay.com/itm/1981-1987-C...dV1K-F&vxp=mtr
__________________
Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
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#17 |
Registered User
Join Date: Jan 2018
Location: MEDICINE HAT
Posts: 77
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Re: Hood insulation: Why? Do you keep it, or don't you?
Definitely have to call BS on the fire suppression theory. Underhood pads were available on some cars as far back as the 50's. They were there to suppress engine noise and improve interior comfort. Prior to the age of plastics they all had metal retainers and rods, I think by the time those melted and released the blanket, the fire would have burned itself out.
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#18 |
Registered User
Join Date: Feb 2011
Location: Lake Charles, LA
Posts: 61
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Re: Hood insulation: Why? Do you keep it, or don't you?
'86 Sierra Classic, I have the blanket as well.
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#19 |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,951
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Re: Hood insulation: Why? Do you keep it, or don't you?
It's for noise suppression. It was stock on the higher trims and optional on the lower trims. You could pick N choose your options back then, unlike today.
It's part of the 16.5 Insulation and Deadener group in the 79-84 parts books... There are a lot of different deadener and insulation pieces referencing floor and engine. I assume deadener means sound-deadener.
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. Last edited by hatzie; 06-05-2018 at 10:09 PM. |
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#20 |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
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Re: Hood insulation: Why? Do you keep it, or don't you?
It was part of the uplevel trim packages, like Cheyenne and Silverado. That's why you don't find it on the lower trim levels, like Custom Deluxe or Scottsdale.
It was primary to control radiated underhood noise. That's why it was also part of the Diesel Prep package. It was made of a flame retardant material, which is perhaps where they understanding came from that it would smother an underhood fire. It certainly would not be prudent to make it out of some type of flammable material. K
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Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ |
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#21 | |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
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Re: Hood insulation: Why? Do you keep it, or don't you?
Quote:
Either somebody added the insulator, swapped hoods, or it was a factory mistake, but it is not part of the Custom Deluxe trim level. K
__________________
Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ |
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#22 |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,951
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Re: Hood insulation: Why? Do you keep it, or don't you?
I made an assumption that it could be optioned on the lower trims because I had two mid-80's Custom Deluxe trucks that came to me with that pad on the bottom of the hood.
Prolly the PO just installed it. Not like it's a super tough thing to do.
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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#23 |
Post Whore
![]() ![]() Join Date: May 2015
Location: Alabama
Posts: 14,635
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Re: Hood insulation: Why? Do you keep it, or don't you?
Keith I know anythings possible....mine came from a fire dept...always stored inside...never wrecked...with 20200 miles on it...I just assumed it was original...
and I mistakenly said mine was a custom deluxe but mines a Scottsdale. ... ye9 is not on my spid if thats the deadner code....
__________________
Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver Last edited by mongocanfly; 06-06-2018 at 04:42 PM. |
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#24 |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,951
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Re: Hood insulation: Why? Do you keep it, or don't you?
YE9 is the top trim package RPO.
GM likes to recycle RPOs and Trim package names. 1973-1974 Base model - Chevy Custom/GMC Custom Z62 - Chevy Custom Deluxe/GMC Super Custom Z84 - Chevy Cheyenne/GMC Sierra YE9 - Chevy Cheyenne Super/GMC Sierra Grande 1975-1981 Base model - Chevy Custom Deluxe/GMC Sierra Z62 - Chevy Scottsdale/GMC Sierra Grande Z84 - Chevy Cheyenne/GMC High Sierra YE9 - Chevy Silverado/GMC Sierra Classic 1982-1987 Base model - Chevy Custom Deluxe/GMC Sierra Z62 - Chevy Scottsdale/GMC High Sierra (Note this change) Z84 - Discontinued YE9 - Chevy Silverado/GMC Sierra Classic http://www.73-87.com/7387info/7387trimlev.htm
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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#25 |
Registered User
Join Date: Dec 2011
Location: WA
Posts: 370
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Re: Hood insulation: Why? Do you keep it, or don't you?
I know for a fact that the hood blanket was included from factory in custom deluxe.
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creatures, deadener, heat, hood mat, insulation, performance |
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