Why do manufacturers put that heavy black insulation on the undersides of hoods? Is it to protect the paint on the hood from heat, or to help insulate the engine bay for the sake of the engine warming up? I ask because I have a new hood for my car that still has the stuff on it, and I want to know if it's important before I go ripping it off and throwing it away. If anyone knows why the stuff is there, let me know.

 

Its sound deading material. Some noodles will tell you your paint will burn if you remove it. If your hood gets hot enough to burn the paint on the hood then you have some serious issues and half your motor is probably melting.

Tearing that ugly crap off my hood was the second thing i did when i bought my car. Every car i have had except one i removed the crap.

 

br()bert is 100 percent right on all counts. It is only for sound insullation, and serves no other purpose than collecting dirt.

Troy
So Cal

 

ahhhhh that's good news!!! I was hoping to hear something like that; I've been itching to pull that crap down and throw it out. It always ends up sagging and it's heavy (thinking about my new lift supports' lives there). Thanks for clearing that up for me, guys.

 

Its a fire hazard that is meant for the garbage.

 

It's not very heavy - unless you engine's been slinging oil and whatnot into it, it should be pretty light. It's not like you'll gain two-tenths on the quarter. Mine looked nasty, and the wife's car had it, but it looked pretty good in hers. Now the hood slams with a hollow metal sound, not a dull thud. And I didn't notice a big sound change either.

 

If any answer could be more incorrect, I'd be happy to hear it... the stuff is non-flammable and can smother an engine fire in an emergency, hence the cheap plastic clips holding it up...

Also, it does serve as a heat insulate.. most cars don't need this, but I can assure you the paint on my hood directly above my turbo isn't smiling. Exhaust manifolds can do a similar job idling for a decent period of time with no underhood ventilation and no insulation.

 

thats complete

I know people wiith much, much larger engines that run ALOT of underhood heat in cars MUCH older than mine(455 olds omega,454's in novas etc) who have had no insulation on the hood and the paint on the hood is fine. The stiff was put their as a sound deading material thats it to reduce engine noise. Its held in place with plastic clips yes, how else would you hold it in place? Weld it? If you have messed up paint on your hood its from something else. maybe the age of the car? Its not from no material on the underside of the hood.


Although you are right about the fire hazard thing,. the stuff isnt flamable, at least mine wasnt.

 

Ehh.. the turbo is a special case for heat, trust me.. might not be as bad if I had a heat shield, but the underhood insulation would be doing its job. As I said, though, MOST cars don't need this. Another note, I mentioned a lack of underhood ventilation.. last I checked 454 novas usually have engine driven fans... there's going to be no lack of ventilation there.

 

It may not burn but I have seen them burn. When they are old and dirty they will burn just fine. Trust me. Find one that leaves black soot on you when you touch it, light her up with a torch, simulating a carb fire.

It will burn. I know its not flammable, but the soot n garbage it soaks up will make it so. It should be replaced about every 5 years. at about 10 they are flammable. 15-20+ and its a torch.

 

Them things are just nasty too. work on your car in the heat n rub your back on one once. There are just nasty nasty things. When they are nice and new, they are nice.

 

I'm going to rip the stuff down; it doesn't sound like removing it is going to jeopardize the new coat of paint when it goes on. Thanks for all of the input, guys.

 

Hmm... yeah.. they do kinda soak up flammable debris rather well.. hadn't factored that in.

 

I agree w/TechSmurf on the first bit- that it was meant to smother a fire. The plastic clips melt first, and then the insulation would drop down over the engine and hopefully put anything out.

But as far as paint burning, well, when I had my car painted back in 97, I didn't put the hood insulation back. The paint was fine for years- until I stopped washing/waxing the car. Now the hood paint looks just like the rest of the car- not worse, not better.

 

I never thought of that.

But if I know Murphy's laws. It says by time the car is in bad enough shape to have an engine fire, the padding will have enough debree to fuel the fire. Not put it out.

They are nice when new.

 

didn't smother my fire/over heating problem

likily the heater hose it burnt thru sprayed the flames.

 

I thought it was Project that had that huge fire and as I was scrolling down reading I was waiting to see a comment from him.

I wanna add my agreement to the consensus. Originally it would put out a fire, but after collecting crap it would probably burn after a few years. Also, whether it is for protecting the paint and dampening the sound or not, it couldn't hurt to help that a little.

 

cool this thread makes me happy , im ripping mine off, how much heat can my lil 3.1 make anyways?, besides mine is also falling apart, looks like cotton ***** under my hood

 

the one on my stock hood is in great shape, but the new cowl induction hood i got does not have it. BUT my new hood has PLENTY of air flow . big scoop OH YEEAAAHHH!!!

on more point on the "protects paint" thing. if the paint was going to be affected, the paint on the underside of the hood would go first.

 

Doesn't Dynamat make a special liner for underneath hoods? It's aluminized, and would look great if someone's engine were detailed. 'Course, it's like $70.. but...

And I think you can buy a new factory-style one from the repop places like The Paddock...

[edit] Huh... I thought Dynamat made one. Here's one by Thermotec: http://store.summitracing.com/partde...rt=THE%2D14001

 

that looks like something trucks put on the side of there truck, the ones that sell food, anyone know what i mean

 

LOL! Those vending trucks are pretty damn shiny... yep, Dynamat does make it, here's a link: http://www.dynamat.com/auto_hoodliner.htm

Ah- here it is; I was using the wrong prefix. The Summit link is: http://store.summitracing.com/partde...57#largerimage

 

i dont know but that looks ugly to me