Guys i am still pretty new to jeeps, so here goes a dum question, what is the reason for hood vents. i have no idea other than release heat, but rain gets in don't it.
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I live in Az. The weather in the summer can be pretty bad. I had a real problem with over heating. After I installed my vents the heating issue wasnt as bad. I dont have a real consern about rain here in Az. and when it does rain it doesnt affect my rig.
Heres some pictures from my tread on the install.


After finding the center points and drilling the holes.




I was thinking about putting the vents on top and trying to figure out what color I liked.


Took a 1.5 inch hole saw to cut the corners. Wanted them to look clean instead of sharp edges.



The hood after I cut the hole. Just used a metel cutting wheel on my grinder for this.



A look a the vents and the size.



And the aftermath. I desided to go with yellow.




Desided to paint the sliders to match.

 

very nice, i just red your thread on your rig, im thinking about the hood vents just got some concern about the rain.

 

Put a set of Gen-right vents on mine. Engine temp dropped and now I can touch my hood in the summer. Haven't had any problems with rain. But like N A I W said, it doesn't rain here much.

 

I have been interested in Hood vents my self. Have read a lot of threads on here. The vents are suppose to help with heat soak and release some of the heat when sitting or going slow. Its not a fix if you have a over heating problem. Something else is wrong if it overheats. Some have been fine with water get down the vents. They say to put electrical grease on all your plugs to keep water out of them.

 

I was amazed how much cooler the underhood temps are with the vents. Mine ran 200-210 maybe 215 engine temps on a real hot day in crawling or standing traffic and you couldn't touch the hood with bare hands. Now it never gets above 210 and you can lay your hand flat on the hood and leave it there.

 

I've had them on mine for about 2 years now (pics can be seen in my album, "evolution of the jeep" under my profile). We get a good amount of rain here and I haven't has a single issue. Big thing is to put di-electric grease on all your electrical connections under the hood. This should be done anyway as water gets in everything any time you drive on a wet road, but it has kept me from having any issues with the vents.

 

Hood vents are a good deal for any XJ, particularly the 4.0 engine which runs hot anyway. A properly placed hod vent will allow more air flow through the radiator and help somewhat with overheating. It is not a substitute for a properly functioning cooling system, but the more air you flow, the better the cooling. I would like to suggest an alternative position for the vents however. The highest amount of vacuum is achieved where the air breaks over the hood. It is also easier for radiator air to escape out of vents near the front of the hood. With that in mind, here is what I did.

 

I used to run the Gen-rights on my YJ. Very little rain gets in and they make a quality product.

 

I used cold air return vents from a hardware store on my XJ(sorry no current pics). Keeps the under hood temp down as mentioned and seems cooler inside on those hot days on the trail. Also helps melt snow and ice off your windshield in the winter . No issues with rain and wet cap or wires and I live in New York. Got ALOT of rain last year!