Show me your hood vents

I know when I open my hood I can not hardly touch or hold the hood scotch rod, much less touch anything else under the hood. The heat being sucked into the intake has to be extreme.
If there is something out there that can vent heat and provide cooler air intake for the manifold its got to be better for the jeep and all components.
I tested this some time ago with a remote thermometer, and at different speeds. The temp at speeds above 20mph was very close to ambient-within 4 degrees Fahrenheit in general. Speeds below 20mph and above 7mph or so, it was within 15 degrees Fahrenheit. Summertime readings at about 980 feet above sea level, stock everything except exhaust header.
 
How did you steel that, I paid just over a hundred bucks for mine in great shape, ended up not wanting to cut my hood so they are on the shel no
I tested this some time ago with a remote thermometer, and at different speeds. The temp at speeds above 20mph was very close to ambient-within 4 degrees Fahrenheit in general. Speeds below 20mph and above 7mph or so, it was within 15 degrees Fahrenheit. Summertime readings at about 980 feet above sea level, stock everything except exhaust header.
And that was with a stock hood or a vented hood ??
 
The only rough idle mine has ever had, and still occasionally has, is after a hot restart. Venting may have helped some. But at least to the extent that mine is vented, is still something that happens sometimes.
I've had this issue with a couple XJs (2000 - 2001) and 3 TJs, all '03 and up. I too toyed with the idea of hood vents, but didn't want to cut the hood, unless it was necessary. On the current TJ, I was having the same issue late this spring when it was warm. Jump in the Jeep, run into the convenience store, come out and start the Jeep, it stumbles. I added the Design Engineering kit in late May, then didn't have a single stumble all Summer (It was a hot one too).

https://www.amazon.com/dp/B015NOKWQY/?tag=wranglerorg-20

20210526_220624-jpg.jpg


FWIW, there is a cheaper kit (I bought both to test them) that is 1/2 the cost. It is of course made in China and the quality is no where near as good as the Design engineering version.

https://www.amazon.com/gp/product/B08TTT8GVM/?tag=wranglerorg-20
 
I've had this issue with a couple XJs (2000 - 2001) and 3 TJs, all '03 and up. I too toyed with the idea of hood vents, but didn't want to cut the hood, unless it was necessary. On the current TJ, I was having the same issue late this spring when it was warm. Jump in the Jeep, run into the convenience store, come out and start the Jeep, it stumbles. I added the Design Engineering kit in late May, then didn't have a single stumble all Summer (It was a hot one too).

https://www.amazon.com/dp/B015NOKWQY/?tag=wranglerorg-20

View attachment 283241

FWIW, there is a cheaper kit (I bought both to test them) that is 1/2 the cost. It is of course made in China and the quality is no where near as good as the Design engineering version.

https://www.amazon.com/gp/product/B08TTT8GVM/?tag=wranglerorg-20
I have had the same DEI kit for years to replace the factory insulation. I couldn't tell much of a difference.
 
  • Like
Reactions: Irun
I have had the same DEI kit for years to replace the factory insulation. I couldn't tell much of a difference.
Interesting. I wonder if elevation has anything to do with it? I've installed two of them and not had a single stumble problem after doing so.

Edit: I also replaced the entire exhaust, from the manifold back, cleaned the block, replaced the entire cooling system, and the condenser, so there is that too.
 
Last edited:
Interesting. I wonder if elevation has anything to do with it? I've installed two of them and not had a single stumble problem after doing so.

Edit: I also replaced the entire exhaust, from the manifold back, cleaned the block, replaced the entire cooling system, and the condenser, so there is that too.
Mostly the same. I should say that this hot restart stumble is not common for me. Just enough that I notice and remember it.
 
  • Like
Reactions: Irun
I've had this issue with a couple XJs (2000 - 2001) and 3 TJs, all '03 and up. I too toyed with the idea of hood vents, but didn't want to cut the hood, unless it was necessary. On the current TJ, I was having the same issue late this spring when it was warm. Jump in the Jeep, run into the convenience store, come out and start the Jeep, it stumbles. I added the Design Engineering kit in late May, then didn't have a single stumble all Summer (It was a hot one too).

https://www.amazon.com/dp/B015NOKWQY/?tag=wranglerorg-20

View attachment 283241

FWIW, there is a cheaper kit (I bought both to test them) that is 1/2 the cost. It is of course made in China and the quality is no where near as good as the Design engineering version.

https://www.amazon.com/gp/product/B08TTT8GVM/?tag=wranglerorg-20
was that picture taken when your Jeep arrived at the dealership from the factory?
 
Last edited:
  • Haha
Reactions: TJ Starting
I put these Genright long narrow vents on a few years ago. The driver's side one is directly over the exhaust manifold, the other just mirrors it. It doesn't do anything for engine temp, but it does let hot air out easier. I originally did it to try to stop heat soak. Of course, about two weeks later I heard about the factory solution.View attachment 283216
Did those louvers seem to help for the heat soak? I don't think I have any cooling issues just that the heat under the hood sticks around when I'm offroad because I'm usually just slowly crawling up or down a trail. It seems like louvers would let that heat escape easier.

Are you referring to the engine heat shield and the fuel rail and injector wraps for the factory fix?
 
I've had this issue with a couple XJs (2000 - 2001) and 3 TJs, all '03 and up. I too toyed with the idea of hood vents, but didn't want to cut the hood, unless it was necessary. On the current TJ, I was having the same issue late this spring when it was warm. Jump in the Jeep, run into the convenience store, come out and start the Jeep, it stumbles. I added the Design Engineering kit in late May, then didn't have a single stumble all Summer (It was a hot one too).

https://www.amazon.com/dp/B015NOKWQY/?tag=wranglerorg-20

View attachment 283241

FWIW, there is a cheaper kit (I bought both to test them) that is 1/2 the cost. It is of course made in China and the quality is no where near as good as the Design engineering version.

https://www.amazon.com/gp/product/B08TTT8GVM/?tag=wranglerorg-20
I may have to try this kit on my 06, I get heat soak pretty regularly in the summer (even with the factory shielding).
 
  • Like
Reactions: Irun
I may have to try this kit on my 06, I get heat soak pretty regularly in the summer (even with the factory shielding).
My factory shielding was basically destroyed, so there wasn't much left. I do still believe venting would be useful, especially on the trail. Although I never did this on my LJ, every time I stop on the trail with it, I pop the hood and let things cool down. Having some venting, without opening the hood, would be useful.
 
I may have to try this kit on my 06, I get heat soak pretty regularly in the summer (even with the factory shielding).
How do you know if your getting heat soak? OBD II reader?
 
How do you know if your getting heat soak? OBD II reader?
The engine will stumble, i.e. run rough, at startup, after a short stop, then restart. It's very apparent.
 
My factory shielding was basically destroyed, so there wasn't much left. I do still believe venting would be useful, especially on the trail. Although I never did this on my LJ, every time I stop on the trail with it, I pop the hood and let things cool down. Having some venting, without opening the hood, would be useful.
I have a vent too, figured the same thing that it would allow some stuff to radiate off a little faster.

How do you know if your getting heat soak? OBD II reader?
I can tell because it feels like (more of) a dog, and it’s audible. As if the engine is restricted a bit. Sometimes you can rev it a few times and it goes away, other times that vapor is a little more stubborn.
 
  • Like
Reactions: JMT and Irun
My factory shielding was basically destroyed, so there wasn't much left. I do still believe venting would be useful, especially on the trail. Although I never did this on my LJ, every time I stop on the trail with it, I pop the hood and let things cool down. Having some venting, without opening the hood, would be useful.
I'm not convinced the flat insulation isn't more of the cause of heat soak. This issue is unheard of in the earlier ones that didn't have the insulation filling the holes between the intake runners. That allowed the heat from the exhaust to just pass through to the underside of the hood. With the insulation, the heat is trapped more under the intake and I think that heats it up more.

There was an issue with some underhood fires from collections of twigs, leaves and such so they added the flat insulation to stop that. I'm not sure we aren't dealing with an unintended consequence.
 
How do you know if your getting heat soak? OBD II reader?
You'll know immediately on a hot restart. It will barely start and then run like shit until the injectors cool down a smidge from the fuel and kill the vapor lock in them.
 
I'm not convinced the flat insulation isn't more of the cause of heat soak. This issue is unheard of in the earlier ones that didn't have the insulation filling the holes between the intake runners. That allowed the heat from the exhaust to just pass through to the underside of the hood. With the insulation, the heat is trapped more under the intake and I think that heats it up more.

There was an issue with some underhood fires from collections of twigs, leaves and such so they added the flat insulation to stop that. I'm not sure we aren't dealing with an unintended consequence.
I'm also wondering if, in some cases, the under hood insulation is a factor. The two Jeeps that did it the worst for me were '04 LJs. Both had hood insulation. As you said, my '99 had no shielding on the intake, or insulation under the hood, and I never had a hot start issue, under similar weather and driving conditions.
 
I'm also wondering if, in some cases, the under hood insulation is a factor. The two Jeeps that did it the worst for me were '04 LJs. Both had hood insulation. As you said, my '99 had no shielding on the intake, or insulation under the hood, and I never had a hot start issue, under similar weather and driving conditions.
No idea actually, I just noticed that the hot start issue didn't show up until they insulated the intake. May not be the actual cause but sometimes correlation is causation.
 
  • Like
Reactions: Irun
I'm also wondering if, in some cases, the under hood insulation is a factor. The two Jeeps that did it the worst for me were '04 LJs. Both had hood insulation. As you said, my '99 had no shielding on the intake, or insulation under the hood, and I never had a hot start issue, under similar weather and driving conditions.
Mine's done it on occasion, no hood insulation and even now with the louver it has happened.
 
  • Like
Reactions: rasband and Irun
No idea actually, I just noticed that the hot start issue didn't show up until they insulated the intake. May not be the actual cause but sometimes correlation is causation.
Do you think wrapping the injectors without the heat shield is the way to go?
You would think some vents placed over the manifold would help.

I still get some heat soak after replacing the factory shield with the DEI kit on my 2004. Not as bad but still happens during really hot summer restarts.
 
  • Like
Reactions: Tob