Hood insulation

Ummmm….engines build up heat in the block, heads and exhaust, it’s why they have a cooling system and an airflow through the grill. All 2024 Tacomas are now turbos and those also build up heat in that the exhaust drives the turbo. Turbos use an oil layer bearing type, have their own intercooler to help reduce charge air temps and every bit of additional cooling you can throw at a forced induction system can make all the difference.

Insulating the hood on a forced induction vehicle is about the last thing you want to do as you are now blocking the heat transfer out of the metal of the hood it self, if anything additional venting it is the better choice.

 

I'm going to guess the hood insulation does very little in making the engine bay hotter.

If you're moving forward at any speed over 15 mph air enters the engine bay through all forward facing openings, and hot air inside the engine bay gets pushed out.

Even when parked on a hot day, you can feel the hot air being evacuated if you stand next to the vehicle with the radiator fans running.

 

If you say so, it’s your truck I guess. I personally would not do it on any forced induction application.

Heat also rises…

 

What’s a good brand of sound deadening to put under the hood? I’ve called every dealership within 100 miles and everyone of them said the actual insulator pad is on back order plus I can’t see paying 400 dollars for an insulator that’s nuts. Any help would be much appreciated I’m not familiar with the sound deadening material and what would be suitable and “safe” for the engine bay.

 

good to know that you have no idea what you are talking about.

 

Yeah I think some people have a fundamental misunderstanding of how engine cooling systems work. Radiant transfer of heat through the hood is approximately 0% of the cooling capacity of the system.

 

That's a great question that I hope someone has an answer for because I want to know too.

 

There’s a video of Sheldon Brown explaining the hood insulation is better $$$ spent for engine noise vs an engine cover… But failed to mention you have to pay 50K + for it!

 

Related question: Did any 2nd gen have a hood insulation pad? It looks like it has all the holes and set up for one but in all the trucks I looked at or pics, I've never seen one with the pad. Do any other trucks have the pad that might fit? (4Runner?) TIA

 

I'm not as familiar with turbo charged 4 cylinder engines, but have owned turbodiesels since the 90s. I downsized into this truck, from an '18 Ram 3500 Cummins. I recall all of my previous turbodiesel trucks having hood insulation/sound deadener under the hood. Of course, a Cummins diesel is LOUD (especially my 24V truck from 2002 - maybe the noisiest diesel I ever owned). But if the worry with the 4G Taco is excessive heat, does a turbo 4 cyl make more heat than a diesel? I honestly don't know. Maybe we'll find out in a few years that SR and SR5 trucks last longer, or have fewer engine/turbo related issues, than Limited and other Premium trim levels simply due to the hood insulator trapping excessive heat(?).

With the diesels, we used to install EGT gauges to avoid turbo damage while towing/pulling long grades, and higher engine RPMs dropped EGTs (which many new diesel owners always found counterintuitive, but true). So this thread seems to be a discussion of sound deadening benefits vs engine bay heat, and if heat is excessive, then regardless of hood insulator or no hood insulator, maybe we should be looking at adding an EGT gauge (I don't recall finding one in the menu's on the dash - found a boost gauge, but not EGT). Or perhaps the aftermarket will respond if people start clamoring for them?

I suspect that Toyota is just being weirdly cheap on this one by not making it standard on all trims. In fact, I would bet in future model years, it will become standard. For 2024, how Toyota forces certain options with their packages is strange to me. For instance, only top of the line packages costing thousands more can get a power seat or dual zone climate control - these are things in entry level models for other brands. But my truck came equipped with a power rear sliding window and heated steering wheel which seem more of a luxury than dual zone climate control or a power seat...? This hood insulator is another odd one since it should likely be standard on all trims with the same engine (as someone noted before in this thread).

 

Exhaust Gas Temperature gauge- now that is something I was curious about too. Seems it would be wise to have it if towing. Theres probably a PID for it and the ECU knows, just need to get the info out of it.

 

Maybe, diesel EGTs will be lower than gas engines, I wasn’t able to find a manifold temp but was able to see the 2 cat temp sensors

This was idle at a light



This was light acceleration ~8-10psi boost

 

Someone could make a killing selling a $20 piece insulation and a few connectors, or even 3M tape, and sell it for $150.

Edit: Anyone have a link to what Toyota uses for the insulation? Maybe I will come up with a kit. Because $400 is insulting.

 

Probably just some type of cheap plastic board/paper wrapped in felt, like what the "skid plates" are made of. lol

 

The 4Runner one actually fits the 3G minus a few clips. I actually ended up with the dynamat one because it was cheaper and lasted 12 years on my 2nd gen. It’s slightly less noise above 3k rpm.

It’s a cost saving measure. 4Runners, Tundras and most of the Lexus models have the insulators with the same turbo engines. Whoever said that the thin pad with no insulation factor is bad for the turbos is really out there smoking it up.

 

Only half right...power seats are available with the middle level upgrade package. Dual zone is only available in top premium package.

 

All... I was very unhappy with the simply awful motor / turbo noises of my new 2024 Tacoma. Note that I am a long term Tacoma owner having traded in the 2007 that I purchased new. So unhappy in fact at 650 miles on the new taco I test drove a Ford Ranger which with a similar turbo drive train sounded much better. I thought so why does the taco sound like marbles in a tin can plus a police whistle and the Ford sounds well OK, certainly not like a sports car or full size truck but OK. So my dealer mentioned to me that the taco Limited and TRD Pro have an under-hood sound dampening insulator. After taking a quick test drive in a Limited I stopped by the parts department and purchased the insulator mat & attaching clips. Installed in the dealership parking lot in 2 minutes and eureka!!! Drove away happy with my new Tacoma TRD Offroad. This should be standard on ALL Tacoma's. Yes I see people saying if doesn't do anything, FALSE it makes a huge difference. Also note that the list price is $405 but can easily be purchased for $280 at the parts counter. Don't forget the 10 clips!
Toyota Tacoma Under-Hood Sound Insulator PN:53341-AK010 and the clips are PN:90467-A0003.

 

Hood insulator $204 right now promo sale at AUTOPARTS.TOYOTA.COM and be picked up at your local dealer free.

 

I ha e used Killmat 80mil ordered from Amazon for several vehicles. Usually pull the entire interior and do full sound deadening as well as under the hood. Just did the doors of the Taco and hood under the factory sound insulation so you can't see it. Made a clear difference. Will be pulling the interior out at some point but my back has me mostly out of commission for a while.

Tip.... use gloves when working with any butyl-based insulation. That stuff is awesome but you will be scrubbing your hands to get it off if you don't cover up.

Also, the front doors of the Ta o were the easiest I have dealt with in a long time. The moisture barrier is an actual plastic panel held on by clips. Super easy to pull and replace. The rear doors are more standard and have a plastic sheet held by a buytl bead. You have to carefully pull the butyl (use a plastic scraper) and not rip the plastic. Putting it back on, you need to really work it so there is seamless contact.