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Insulation under hood????

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Old 07-01-2010, 09:16 PM
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Insulation under hood????

Does anyone know if taking out the insulation under the hood will hurt anything? It just seems to me that there would be more room under there for more air circulation, especially right over my AC air compressor that gets super hot.
Old 07-01-2010, 09:59 PM
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Re: Insulation under hood????

A lot of people will say no it doesn't hurt anything but I will disagree.

If you drive in a climate where it doesn't snow and ice I don't see why not get rid of it.

From my experience if you don't have it in really harsh cold it can cause problems. This is my personal observation mind you but I owned my 86 z28 for probably 4 years before removing the hood insulation and never had a problem in the winter. But after removing it, in the dead of winter it has problems with the windshield wipers freezing (at the arms/joints, not the blades) and building up layers of ice on the windshield starting from the bottom to up while driving. Like I said though only in the harshest of colds does this happen.

It may not sound so bad but 2 winters ago while driving in Friday rush-hour traffic during a snow storm my windshield completely iced over just seconds after the wipers froze still. So as if driving a camaro in a snow storm isn't bad enough now I can't see out the front window in thick traffic, can't see to pull over even. Yeah, that was fun. Luckily for me everyone had on their lights, I could still see that and made it home in one piece.
Old 07-01-2010, 10:19 PM
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Re: Insulation under hood????

So, is the purpose of the insulation to keep the extreme heat from melting your paint on the hood?
Old 07-01-2010, 10:21 PM
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Re: Insulation under hood????

Every vehicle I've ever owned, 3rd gen or not.....Steel hood or fiberglass hood.....I've pulled the insulation off right after buying the car (or putting on a fiberglass hood) or even getting a brand new paint job. And I've never once had a paint problem on OEM or aftermarket paints. And all here in central Texas, where it was 104 last Saturday at the TGO Statewide Gathering.

I've also always pulled the rubber strip off the back of the underside of the hood that seals to the firewall, to provide another exit for the underhood engine heat to get out.
Old 07-01-2010, 10:30 PM
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Re: Insulation under hood????

I've always removed all the underhood insulation the day of getting each car, and I never once stopped to consider if it was a problem in the winter. I never had my wipers freeze, but I have had issues with keeping the windshields clear. I guess it could make some difference.
Old 07-01-2010, 10:46 PM
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Re: Insulation under hood????

I have heard of people removing that strip above the firewall. Does water get down into the engine compartment? Is there any problems it causes by not having it??? I think I might pull mine tomorrow?????
Old 07-01-2010, 10:56 PM
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Re: Insulation under hood????

Originally Posted by stahrman0612
I have heard of people removing that strip above the firewall. Does water get down into the engine compartment? Is there any problems it causes by not having it??? I think I might pull mine tomorrow?????
If water does, it has never caused a problem on any of my cars. I guess with bad/bare wiring it could.
Old 07-01-2010, 11:36 PM
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Re: Insulation under hood????

Even with the problems I've had I wouldn't put it back. It only happens when it is like below 0 and snowing which is like a week or two a year around here and most of the time I'm not driving. But it is something to keep in mind though, that could have ended really nasty.

One thing that is nice about it is you can here your massive secondaries go "Bwaaa" on your Qjet better.. gotta love that.
Old 07-02-2010, 01:13 AM
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Re: Insulation under hood????

Unless its clean & new, its just a fire hazzard, it can't catch fire ,the 20+ years of dirt n grime that build up in it makes it so. Plus it just makes for a dirty back.

Never had any problem in the cold, dunno where that myth is from and no the paint don't give a crap either.
Old 07-02-2010, 02:01 AM
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Re: Insulation under hood????

Originally Posted by Gumby
Unless its clean & new, its just a fire hazzard, it can't catch fire ,the 20+ years of dirt n grime that build up in it makes it so. Plus it just makes for a dirty back.

Never had any problem in the cold, dunno where that myth is from and no the paint don't give a crap either.
So my past experience is a myth? It must have been something else causing the freezing air flowing under my hood to freeze the wiper levers under the bezel and progressively cover my windshield in ice from the hood up while driving on the highway.

The way our cars are designed aerodynamically speaking that is probably one of the least areas besides the rear bumper where air is hitting in factory trim. Remove the hood liner and rubber and that's changed completely, and that's why we do it, to let air out. Well when that air is sub zero and it's snowing you don't think it could freeze?
Old 07-02-2010, 04:11 AM
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Re: Insulation under hood????

Originally Posted by Doom86
So my past experience is a myth? It must have been something else causing the freezing air flowing under my hood to freeze the wiper levers under the bezel and progressively cover my windshield in ice from the hood up while driving on the highway.
Your hood to cowl seal was missing then,

Never had any such thing happen and we get nasty winters here in Ohio.
Old 07-02-2010, 07:27 AM
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Re: Insulation under hood????

I only remove it to reduce front-end weight.
Old 07-02-2010, 08:56 AM
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Re: Insulation under hood????

Originally Posted by Stephen
Every vehicle I've ever owned, 3rd gen or not.....Steel hood or fiberglass hood.....I've pulled the insulation off right after buying the car (or putting on a fiberglass hood) or even getting a brand new paint job. And I've never once had a paint problem on OEM or aftermarket paints. And all here in central Texas, where it was 104 last Saturday at the TGO Statewide Gathering.

I've also always pulled the rubber strip off the back of the underside of the hood that seals to the firewall, to provide another exit for the underhood engine heat to get out.
I do the exact same things when I bought both of my thirdgens. It has never caused me a problem on my '83 Z daily driver. Like stephen said, if you have bad wires then it could cause a problem, but no problem so far.
Old 07-02-2010, 09:32 AM
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Re: Insulation under hood????

I think the insulation and rubber seal have more to do with what is often referred to as the appearance of quality. In some of the other threads where people complain about rattles and such, I feel that both of these are there to reduce noise and stabilize the hood. It may have also helped in the winter months as far as keeping heat in and the snow from melting and refreezing on the hood.

I actually added the rubber strip on mine because I was tired of watching it rattle around while I was driving. I didn't have any heat issues since it's a stock V6. lol
Old 07-02-2010, 12:16 PM
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Re: Insulation under hood????

Originally Posted by Scorpner
I think the insulation and rubber seal have more to do with what is often referred to as the appearance of quality.

The reason folks remove the hood to cowl seal is they think it will give them cowl effect cooling like how the intake for nascar is back there, taking advantage of the low pressure area. But its not a good idea in the winter.
Old 07-02-2010, 01:28 PM
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Re: Insulation under hood????

Seems to me that removing the seal would help cooling all summer, and keep the windshield clearer all winter.
Old 07-02-2010, 01:53 PM
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Re: Insulation under hood????

Originally Posted by Atilla the Fun
Seems to me that removing the seal would help cooling all summer, and keep the windshield clearer all winter.
Well if you or anyone else likes it that way Ill gladly take your cowl to hood rubber seal if in good shape.
Old 07-02-2010, 06:12 PM
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Re: Insulation under hood????

When I removed my insulation, the only difference I noticed (besides not getting my head dirty every time I was under the hood) was that light rain would steam off the hood. It was actually kinda cool.
Old 07-02-2010, 06:25 PM
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Re: Insulation under hood????

On some cars, that hood to cowl seal helps keep heat and smells out of the interior. I think I would keep it. What hurts you paint are UV rays. Remember, most paint is heat cured anyway.
Old 07-02-2010, 07:02 PM
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Re: Insulation under hood????

Well thanks for all the advice!!! I ended up taking the old dirty, grimy, grease stained insulation off and painted the underside of the hood. Looks very good now. I left the rubber strip on the hood because I'm just not sure about any real benefits it has taking it off, I don't have any overheating problems and don't like the idea of rain maybe getting down into my wiring.
Old 07-02-2010, 07:27 PM
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Re: Insulation under hood????

keep the rear seal . this subject has been thrashed in the past . the blanket under the hood is for sound . ( if i have a sound under the hood i want to hear it ) mine has been removed on all my cars . the seal on the rear of the hood keeps fumes/smells from engine from getting into A/C system in stop and go traffic . the A/C picks up outside air from the base of windsheild . ( notice the screen thing at the base of the hood & wiper arm area ) people have said if you have fumes you have a leak of some kind . well if they an engine you can eat off O.K. . if you are a normal person , you have some dirt under the hood that could/will give you fumes/smell . removal of the seal will allow A/C to pick them up and send them into car . enough said , if you remove seal dont throw it away . you will want to re-install it later . good luck .
Old 07-02-2010, 08:52 PM
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Re: Insulation under hood????

Originally Posted by Chainshot
On some cars, that hood to cowl seal helps keep heat and smells out of the interior. I think I would keep it.
Ding Ding Ding we have a winner, the fresh air vent for the HVAC is right there.......
Old 07-02-2010, 10:02 PM
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Re: Insulation under hood????

I've never removed the seal, because getting moisture in the dizzy is just begging for a costly and inconvenient problem. Mine's dry-rotted, but I'd bet "A&M Soffseal" can provide a nice new replacement. If not them, then "Metro".
Old 07-02-2010, 10:26 PM
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Re: Insulation under hood????

I actually found the seal for mine on a junk yard hood, some of them are in really good condition. Same goes for the rear hatch seal BTW.



Good info about the A/C intake. I didn't know that.
Old 07-02-2010, 10:40 PM
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Re: Insulation under hood????

Originally Posted by Scorpner
I actually found the seal for mine on a junk yard hood, some of them are in really good condition. Same goes for the rear hatch seal BTW.



Good info about the A/C intake. I didn't know that.
Just note set on MAX AC on all GM cars the fresh air vent is closed.
You can also put it on max ac but put the temp slider on hot, and its like max heat as the fresh air vent is closed anytime on max ac, temp setting don't matter.

Last edited by Gumby; 07-02-2010 at 11:02 PM.
Old 07-06-2010, 08:19 PM
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Re: Insulation under hood????

I reluctantly removed the insulation on my IROC , and nothing bad happened. No blistering of paint, no extra noise, and I wouldn't even think about driving it in the snow and ice.
Old 07-06-2010, 10:06 PM
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Re: Insulation under hood????

Its always nice to come across a thread with helpful info like this one.

wish i never took my seal off. To the junk yard i go.

Last edited by Chrome on Rust; 07-06-2010 at 10:15 PM.
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