The right way is to address to cooling system. Adding hood vents is kind of a hack, like gapping your hood hinges, but not as ghetto as removing the hood entirely. :thumb:

 

I’m imagining a hood strapped to the roll cage in lieu of a bikini top. This could catch on.


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It'd be nice to add a better/larger rad, but a good one simply doesn't exist unless you get one custom made. The Mushimoto and the Flex-a-lite both get pretty bad reviews. Hoping someone proves me wrong because i need to swap mine out.

 

This is the radiator I bought:

https://www.amazon.com/Primecooling...p/B071L2CG8G/ref=sr_1_7?ie=UTF8&qid=1525675988&sr=8-7&keywords=Jeep+jk+radiator

Good price, works great but it is a tight fit and you need to use self tapping screws or tap the standoffs. Mine did start to leak after about a year of use but I could not determine the origin of the leak. Sent a picture in to Prime Cooling and they sent out a new radiator the next day, it does have a lifetime warranty.

 

With 35s, bumpers, winch, armor etc I only see high temperatures when going up a long grade fast when it is hot. So hood vents are not required.
I'd disagree about vents not being any good - with cooling systems the main factors are coolant flow and air flow. The radiator efficiency doesn't increase much as you make it thicker.

 

I have a Hard Rock JKU with Power Dome hood. I enlarged the hood vent openings and I also added fender vents. I am amazed how hot the fender vent area gets. Everything has to help.

 

For those of us that live in relatively temperate parts of the U.S. (e.g. NOT the desert Southwest)

Actually, I do live in the desert southwest (106 today), and my Jeep runs cool as can be. Does anyone suffer from overheating as a normal course of events? And, no, I don't believe that expanding the vents in my Hard Rock will have any measurable impact.

 

I wouldn't say critical, but I think it can help. JKs are designed to run hot. And with the exception of people with actual, traceable, and repairable problems, the JK does a pretty good job of managing the heat... when it's stock. Big tires, blocked airflow to the radiator, high load levels, steep grades, etc. can put the JK in a bind to keep itself cool. The whole point behind the cooling system is to keep the engine in the appropriate heat range. If more heat is being generated, it has to go somewhere. Most Jeeps still manage the extra heat-load well, but others could benefit from having escape from the engine compartment. Heat wants to rise, so if given a path, it will do so. It will allow for less ambient under-hood temps and allow the radiator to have an easier time managing the extra heat.

In all reality, what matters more is if you like the look of the vents in your hood.

 

I would like a vent in my hood. All that crawling around in 4L on hot sunny days. My fan just blasts the whole time.

 

I added my PS hood louver because I liked the look and I didn't mind cutting huge holes in my hood. I didn't have any issues with overheating. I will tell you crawling around in 4LO it is amazing the amount of heat that pours out of the hood. So do I need it? Nope... but it certainly hasn't hurt anything either.

 

Honestly, I think there is plenty of air circulating around a Jeep engine with a good fan and remember most of the cooling will take place in the coolant system.
Hood vents just keep the hood cooler and after-all us lazy humans place our hands there to gage the temperature.

The only time I am truly worried about engine temps is off roading in LOW range. Keeping the RPM's down seem to work for me.

 

The idea of taking a sawzall to my perfectly good 2018 hood just to insert some plastic vents, or worse yet to sheet metal screw in something like a poison spyder louver panel, definitely doesn't sound appealing. Neither does the cost of a color matched a 10th Anniversary Hood, considering that even those vents are mostly faux unless you dremel their openings.

But the side vents I actually like the look of... I wonder if anyone has done any tests to determine if these provide a measurable change in cooling on a hot day?

 

Does the airflow through the engine force air out those vents, ie, are they in a high pressure area?

 

Yes it does, that is why it the surrounding metal is hot after driving. I got the idea for putting vents there from the JL. They said on the JL was to reduce hood flutter which obviously means on the JL they are allowing air out of the high pressure under the hood. The same thing is happening on mine.

 

Not at all necessary. I live in Phoenix - it doesn't get much hotter than this.

 

Answering the question asked.... How critical? No matter what the build is - Not critical.
Engineers (despite how much fun they are at parties) are trained and charged with designing correct systems, not the least of which ....the cooling system on our Jeeps.
I would imagine "overbuilt" is usually the goal for something as critical.
That said, Heat is the enemy of most things mechanical. I have a HR hood and my vents are "open" like they were designed to be. Do they work? Yes, very well.
Getting the heat out of my engine bay is just something that makes sense to me.
IF my hood was sans factory vents (I have Jeeps that are closed hoods) I have no plans to cut them open.
FWIW, one mans opinion.

 

Engineers are also charged with designing something that will work properly for the duration of the warranty period.

Heat under the hood will eventually take a toll on rubber hoses, electronics, and vacuum lines, though usually not until past the warranty period.

When bean counters are given sway over engineers is when you get cars like my 2002 Camaro SS where the transmission and rear axle were know to fail regularly at around 80-90k miles.

The bean counters insisted that the 4L60E instead of the 4L80E and the 10 bolt rear instead of the 12 bolt rear were fully sufficient to live past warranty claim periods, and they were correct.

My 10 bolt rear axle was chewed up at 75k and my 4L60E transmission had a sun gear tooth in the drain pan at 90k.

If the rest of the car had been as good as the LS1 engine I would've kept it forever.

Unfortunately, it was a great engine surrounded by a bean-countered to death Chevrolet.

With FCA's reputation. I'm sure there is LOTS of bean-counter engineering going on.

 

Interesting you said that, I just saw a JKU with 40k on it at the dealer. It was getting some powertrain work and the hose braiding was literally crumbling if you touched it. Mine was bad but I have more miles, I was surprised when the tech pointed this Jeep out after I asked about it, he said by 20k the braiding is falling apart already and getting brittle. I didn't know about this until having to replace the oil cooler housing, the crumbled braiding was all over in the valley.

 

I will say that before I cut open the vents on my 10A hood my rad fan would run WAY more often and for a longer period of time. However, I wouldn't call them critical. I do find it kind of cool when you can see the heat coming out of them. Like when stopped at a light or while off-roading. It's also the first place the snow melts in the winter.