Hood Vents

Like many Cherokees, my '91 tends to run a little warm sometimes(usually 210, increases when going uphill on a warm day). I believe that a large part of the problem is lack of air flow under the hood. I am think of cutting a 4-6" hole on each side of the hood, about 2/3 of the way back and then covering them with reversed hood scoops.

Has anyone done this or something similar? Results? Suggestions? Thanks.

Ben (Dawg)


PS: After several years as a freeloader, I have finally sent in my $ for a two year membership. I'll be part of the new Pacific Northwest Chapter.

I've seen several XJ's with hood vents.The vents off of a Pontiac Grand Prix look really nice.It's really what ever you prefer,lots of options out there... member#579.

You could also get a couple of 4" - 5" lengths of small square tubing and use them as spacers between the hood and hood hinges. That would raise up the rear of the hood just enough to provide some venting. Most wouldn't even notice it. The ones that do will be chicks that dig hood mods.

"Everyone's Jeep is different. Mine has paint and the tires are round"

Max, that is an interesting option. I've considered removing the weatherstripping from that end, but spacing the hood a little taller is probably what I'll do now, thanx for the suggestion.
Someday I will louver the hood. It will hide my hail damage, run cooler, and look cooler too
Crunch

My budget hood vents from HomeDepot.
Set me back for less then $5 including of can of paint!



There are more fancy DIY vents out there, just have to search.

Yeah

http://photos.yahoo.com/bc/satanjeepsanonymouscom/lst?.dir=/XJ+Hood+Vents

They do work well at low speeds (easy to see the heat boiling out of em when crawling or waiting...) -- I've got some pressure data somewhere, it indicates some pressure venting, but nothing like a breeze...

... the big difference is in "hot-soak". When sitting somewhere engine on or off the underhood temps climb way up and have time to soak through the air intake and manifold and all even the TB gets really hot -- after the vents, the temps on all those surfaces and, by inference, the intake air charge, was much lower (again - the datas somewhere on that desk of mine with everything else, waiting for the articles). This makes a noticeable improvement in re-starting and torque after sitting for a bit.

Many of the discussions include "water" comments -- for my part - I live in Colorado - like 30" of rain a year even that, until the engine bay is sealed at the bottom, I don't see any reason to be conserned with "water" from the top...

Here is a link to my vents. They are out of a Z car. I did cut through the hood supports but have not noticed any loss in hood strength. I have the sheet metal to strengthen the area I cut through the supports but have been to lazy to finish.

http://www.5pennies.us/Myjeep.htm

Check this out, the nicest looking install I've seen, gonna doit to mine, and the wife even likes it!
http://www.ericsxj.com/vents.htm

ok, i understand that hood vents release some heat, but what about water? How does it keep water out...or does this even matter?

My plans are to cut three or four holes in the hood at the back and run some stereo amplifier cooling fans to blow out the hot air.

imma honky said:

ok, i understand that hood vents release some heat, but what about water? How does it keep water out...or does this even matter?

Click to expand...

water wont hurt unless it gets into ur intake (which most likley it wont) think of it this way.. when ur driving on a rainy day water splashes up to your engine and some water goes through your radiator and blown by your fan smack onto your engine... so no.... no worries

**DOH**(smacks head) alright, im a tard. I shoulda thought of that. Well, im still learning about cars......

the fronts are inverted to create flow at speeds.
the rears are from a lebaron turbo.
Havent tested it at speeds but at idle I can keep idling for hours. Which is much better than it used to be. I got the Heart transplant under their (V8) and it used to overheat almost always in traffic.
I cut partially into the support for the rear ones. but they are placed directly over the exhaust headers. You 4.0l guys can arrange the lebaron vents so that u dont have to cut the supports. They are fiberglass and will hold up well, Just use Hi Temp paint cuz they will vent!

THE_OWL said:

the fronts are inverted to create flow at speeds.

Click to expand...

The way my '87 sits that area (leading edge) is kinda turbulent above 30 or so... If you do "create flow" you'll be stuffing air in in there decreasing the flow potential by increasing pressure behind the radiator... (much like the front diff's ability to kick-up a little pressure at some odd lift heights.)
... hope it works out for ya (the V8 oughta be a fun run!)

Are there any companys that do this specifically? I hae noticed that my stock engine heats up real good on just mild trails. (hate to think what it will do with a lift and rock creepering).....

http://dpgoffroad.com/hood.html

[The way my '87 sits that area (leading edge) is kinda turbulent above 30 or so... If you do "create flow" you'll be stuffing air in in there decreasing the flow potential by increasing pressure behind the radiator... (much like the front diff's ability to kick-up a little pressure at some odd lift heights.)
... hope it works out for ya (the V8 oughta be a fun run!)QUOTE]

Thats why I have vents in the back pointing back. My Radiatir is run by shroud and dual electrics only.
When I spray carb cleaner (under pressure) right into the front vents it mists out the rear vents. The way I figure it, it creates air flow right at the top inderside of the hood in a thin stream
intake, exhaust

I did the spacers between the hood and hinges. I used some the factory spacers and two pieces, one on each side, of square aluminum tubing.

I drove from Orange County to the Rubicon and back with them. I do know they let out the heat. In my case they really did not help, but I may have bigger problems.

The reason I know the heat escapes is that on my 96 the heat goes right into the cabin air intake. So if you run the vent only you will get warm to hot air out of the vents. We came back at night 10 p.m. or so and could definately feel the difference in temperature from outside to that of the vents.

just my experience.

i louvered my hood on my 91. it did not help any with overheating. a new style fan with the curved fan blades was the best thing i ever did for the overheating. but the louver or vents do look cool. jack

My '91 4.0L used to run hot as a blast furnace too. Then I ran some Permatex Radiator Flush (the hydrochloric acid type) throuth the radiator and cleaned it out.
It no longer OVERheated but still ran all day in the 210-225 range. This, at least to me, was not tolerable.

So, I went down to Autozone and bought the best lower temp thermostat that they had. I believe that stock was like a 192* and I bought a 180* stat.

Now, under normal and fairly hard street use it runs much cooler and the hood stays alot cooler too.

It still heats up to 210* sometimes, like when I idle on a 95*F day with the A/C blasting for ten minutes, or when towing a Bronco II up a huge hill. But I have never had it get above about 215 since. Also, no problems with the computer keeping the engine in "choke mode" either. No performance problems with the lower temp stat whatsoever.

I believe that 2 things kill wires and hoses under your hood: heat and oil. Keeping my underhood temp about 20 degrees cooler most of the time should really help prolong the life of my stuff in the engine compartment.

I also have a pair of the Lebaron hood vents sitting around, I just sanded them and primered them today. They cost me $4 along with a license plate holder at the local boneyard. My '91 Sport has a lot less supports under the hood than the later models do, so I have much greater freedom of where to put the vents than the guy at www.ericsxj.blah.blah.com does. My buddy (mikal) just put some of these vents on his '97 and you can see lots of heat rising out of them. I figure, the cooler the better, and I think they look COOL (pun intended) to boot.

Good luck, sry for the life story...... zzzz.... zzzz.... zzzzz........:speepin: