Hood vents, do they work?

[napajeep]

For those of you that have done them, did they make that much of a difference? More of a difference at low speed or high speed?

Mine tends to run warm, and I spend some time in 105+ temps, want something to help keep it cool.

[Z]

For those of you that have done them, did they make that much of a difference? More of a difference at low speed or high speed?

Mine tends to run warm, and I spend some time in 105+ temps, want something to help keep it cool.

Kevin showed me a cheap mod for this - remove the plastic cowl over where the wipers are and remove the seal at the back of the engine bay, this will allow air to flow out of the hood. It helps a LITTLE. I think there are still some obstructions there, you'd probably be able to cut some ports between the wiper compartment and the engine bay.

I think this would be just as effective as hood vents.

[LouisianaZJ]

mine work pretty good for LOW speed/stop and go w/ the AC on. I my vents right over the intake manifold on my 4.0L XJ. I can see the heat waves rising up in traffic.

[napajeep]

Was there a marked difference before vs. after?

[LouisianaZJ]

in low speed/stopped w/ AC on, yes. It would creep up to 230*, now it stays below 215*

[corrupt143]

I just put 3 washers on each side (on the post closest to the windshield) on the hood hinge, kinda like a cowl hood. I can tell a difference when wheeling and in town. A decent mod for free.

[TrojanMan]

I just put 3 washers on each side (on the post closest to the windshield) on the hood hinge, kinda like a cowl hood. I can tell a difference when wheeling and in town. A decent mod for free.

I did this too.


The 5.9L style vents work well also, they take advantage of negative pressure to suck hot air out of the hood. Vents like that work better while moving - the faster the air moving over the hood the more negative pressure you encounter.

[Alaska ZJ]

I noticed a significant amount of improvement in Heat stabilization when I put my 45 cent dryer vents on. Seriously.

I used to get up to 220+ pretty fast on the trail and afterward I rarely went over the standard 210. It was worth the 2 bucks and 45 minutes to do it.

[DJJordache]

when I did mine I did the yarn air flow test to find the lower pressure areas on the hood and came up with about the same spot that the 5.9L vents are.

here are some pics of the STOCK 5.9L hood vents NOTICE the SMALL holes...





here are a few pics of the placement of my vents that are from a Pontiac GTP and yes I did cut out the part of the bottom of the vents to allow more airflow.






you can feel the hot air pour out of these vents at idle and can only image the air flow at speed since the location I put them was a lower pressure area before and SHOULD help even more with heat evacuation at speed.
also these pics are old and I' don't have the insulation on the underside of the hood now either.

[J B]

I noticed a significant amount of improvement in Heat stabilization when I put my 45 cent dryer vents on. Seriously.

I used to get up to 220+ pretty fast on the trail and afterward I rarely went over the standard 210. It was worth the 2 bucks and 45 minutes to do it.

Alaska, you got any pics of this? It sounds like a cool idea...

[WestexZJ]

For those of you that have done them, did they make that much of a difference? More of a difference at low speed or high speed?

Mine tends to run warm, and I spend some time in 105+ temps, want something to help keep it cool.

I did the vents and while the look cool I didn't notice that big of a difference in my temp.

I did however notice a huge difference when I installed my Taurus e-fan and the Delta controller. Just returned from GSW 2007 temps on the trails were in the 105 range and I never exceeded 180 on my temp gauge. Ran the AC on the trails and still remained at a constant 180.

IMO if you ant to stay cool swap in a Taurus e-fan and get a 180 degree thermostat.

[daverobb@rewedmonton]

I have the Pontiac GTP Louvers in the stock 5.9 Limited location in the hood of my '98 ZJ Laredo. The engine is a 5.9 and the louvers reduced the under hood temperature and above hood temperature to the touch. Coolant temperature dropped about 10 degrees Centigrade when off road or pulling the travel trailer. The hot air pours out the vents at idle with or without cooling the fan on.
I also removed the weather strip/seal at the back of the hood, but the intake vent then pulled all of the hot air into the cabin I. So, yes it helps cool down under hood, but makes the a/c work harder and nulifies the in cabin vent effect without the a/c on. I have since replaced a portion of the seal in front of and around the vent, leaving an air gapp of about a foot on either side.
I plan to over ride the electronic cooling fan controls with a dash mounted switch so that I can manually control the electric fan, but have not as yet figured out how this will effect the computer.

[napajeep]

Thanks for the responses. Last year I removed the rubber piece at the firewall, installed a 180 t-stat, put in a 3 row radiator, changed water pump (Mopar). I have thought about the e-fan route, but the problem seems to exist more at high speed, and some when on/off the gas. Oddly enough, if it idles it cools down a bit.

[WestexZJ]

Thanks for the responses. Last year I removed the rubber piece at the firewall, installed a 180 t-stat, put in a 3 row radiator, changed water pump (Mopar). I have thought about the e-fan route, but the problem seems to exist more at high speed, and some when on/off the gas. Oddly enough, if it idles it cools down a bit.

Well that changes everything! I never had a problem at anything above crawl speed, so I don't know what to tell ya.

Good luck

Ronnie

[LouisianaZJ]

sounds like a coolant flow problem, but you replaced all that stuff...

maybe running lean at high RPM's?? electrical/sensor problems

[napajeep]

Yeah, it's been kind of a pain. It doesn't overheat, just runs warmer than I would like (I don't want it any warmer than 210), it gets up to 230 at times.

As far as coolant flow, I have flushed it (water pump removed, through the water neck), put a fail safe t-stat in (in open position), new fan clutch, and all of the previously stated items. It does have an ARB bumper, which I think is a major part of the problem. I think it disrupts the air flow. Also when at the higher speeds, I think there is pressure under the hood from air flowing underneath, then being thrust upward by the front axle.

I might try the washers under the hinge bolts before putting holes in my hood.

[LouisianaZJ]

do you have a winch on the ARB?

[napajeep]

No winch at the moment, but that hole is currently covered by the license plate. Made no difference with or without.

[jsteves]

I have been having similar problems for past 2 years. It started with a leaking stock radiator (of course). I replaced it with a 3 row one followed by a flowkooler pump, 5.9 elec. fan, 180 tstat, and finally huge hood louvers.

Mine, like yours, seems to only overheat when I hit the highway. On the trail or around town it does great. So, what I am wondering, does the 3 row radiator not allow enough air flow to actually cool the water enough when at speeds or heavy loads...Scott (Colorado5.9) mentioned at one point that he thought people had had issues with the 3 row radiators as well.

At this point, I pretty much have no choice other than trying a different radiator...I'm tired of not being able to use the A/C. I will report back when I make the swap.

[Alaska ZJ]

Damn no pictures on the old AKX site. I will go take a picture of the hood tomarrow for you. I still have it in the garage.

[chadjans]

4 inch pvc pipe vents: http://www.imagestation.com/album/in...?id=2134157966

[napajeep]

I saw those on your buildup, how much did they help? You live in AZ, doesn't get a whole lot hotter than that.

[Katesdad]

I googled hood louvers and found this place called raceace.com might be worth a look. They arent cheap but they have pics of jeeps with them. Id look at a junkyard first for those ponitac ones, they look great! Seems to me in the 80s it was a big deal to have a louvered hood. But they were cut or pressed out. Like on the sides of a 32 ford coupe. I might be just spewing out BS too.

Ok it wasnt BS I found louver dies at Eastwood.

[Nonstop]

That site does have a nice product a little mad max looking for my rounded schoolbus WJ...not that it is any indicator of anything but the site also shows them on the Hood of an NSX.....
That kinda shit is a So.Fl spececial where you'd actually catch the owner of such a car bragging about the performance gains..

most louvers in yards around here will cost ya in the neighborhood of $60 so I am hoping to just grab a set off a GP..

[MBATF]

I have actully just ordered a set of Hood Louvers from raceace.com 2 days ago. I will be installing em once they are arrive. I will give some updates.