xpsniper

Hey Guys,

Was doing some research on what to put on the hood to help cooling as my XJ is starting to borderline red zone on some of the trails.

So I'm looking at functional cooling for the engine and everyone seems to think one of the three is better than the others and its all over the place.

Does anyone know which is better for cooling the engine?

Also, Forward or Backwards direction aswell.

Thanks

tymatt

First off, check coolant system. Make sure it has a good flush and new coolant and thermostat. When creeping on trails, the direction of a scoop wont matter much. Vents seem to do a good job of removing under hood heated air. If you wanted the maximum effect you could install a small electric fan to draw heat out through the louvers.

Atmos

scoops, arguably do not belong on a jeep. vents are nice but I went with a cowl because it wouldn't allow any rain water to get in. plus, I liked the look at the time

if your fan is at the front of the engine my idea was that there should be a place for the air to escape out the back. which it did. it dumped massive amounts of hot air. how much does this do for actual engine cooling? can't say. all I know for sure is that I had less hot air in my engine bay

best thing I ever did for my XJ's heating woes was fix my electric fan and put a switch on it. more airflow through the radiator really did the trick. this is why dual electric fans is at the top of my list for engine cooling mods now.

Ianf406

I went with vents.. They work great while idling. You can see the heart pour out of them. Theve been on there for a few years with no problem.

Tom95YJ

I had 2 rear facing scoops on my XJ that I replaced with Napier vents. They both keep water and snow out and help cool the engine bay in the summer months. I will say the Napier vents allow way more air to pass through then my scoops did.

andrewmp6

Like said make sure your coolant system is in top shape and working like it should.If everything is fine then try some water wetter it will lower your coolant temp enough to keep it from over heating.

xpsniper

Thanks for the discussion.

Cooling system is fine. Runs at 2/5 the gauge on highway and 1/2 on slower roads.
It's only now that my rig has 31s on and it has to work harder in soft sand and up hills etc (can't afford a regear at the moment to make it easier)

Vents are looking the way to go and them might ditch the a/c fan for a bigger electric fan on a switch.
My a/c is stuffed anyway and turning the heaters on is what I do when it gets hot, ends up making me hot instead

Fred/N0AZZ

You should have said that in the beginning first thing is change the Gears! Those 3.55 would suck in the sand with the 31's, a set of 4.56-4.88's would not pull the engine down as much and keep it cooler.

IMHO the only XJ's that need hood scoops/vents are those that are setup as crawlers (Real Rock Crawlers). A trail XJ like mine or most in general will not have any issues with a good (well designed) cooling system.

I'm sure there may be one that you come across some that will need aftermarket cooling components other than stock to do the job but not as many as think they do. As they are just masking another problem instead of fixing it, it happens all the time with any modified cars.

YMMV.

xpsniper

I'm just a worrier when it comes to the heat. I just want to keep it as cold as possible to avoid any issues possible.

With the gearing, is it hard to come across a set of increased gears and how much do you need to change to fit them?
I've always seen that its the whole axle that gets changed but if there's a way to do it without that it might be a viable option for the cash that I have.

SteveMongr

I have dealt with this type of driving for many years.
It sure helps to use 4-lo in the soft sand and while climbing. It's a good range for 31"s and stock 3.55 gears. Temps will drop as well, especially the transmission temp.
Your best bet for in my opinion is the ZJ fan clutch for the V8, NAPA part #272310 (May not work with 3 row radiator).
Flows more air than stock, especially at idle and crawl speeds, the AC can run at idle, no creeping up of temps in traffic or idling. Driving in deep summer sand, my engine temp runs steady. Transmission heats up in 4-High (180-190 F). In 4-lo tranny quickly drops to 150F.
It was the key component to stabilizing temperatures. No vents. Large aux tranny cooler mounted in front of mechanical fan.
I also have the electric fan on a switch and good functioning cooling system with 195F thermostat.
Engine temps are 205 on road, and 210 on the beach.

EZEARL

I raised the back of my hood last summer. Knew it wouldn't lower the engine temp,which I have no problem with,but I wanted lower the underhood temp. After making and installing a set of 3/4"x3" spacers I decided it made the hood too high for my tastes so I made a 1/2". By removing the rubber seal and bumping that shelf down a bit full length I got an even 1/2" gap all along the opening (I can still seal it if I want). Adjusted the hood all the way forward and all is good. Hood latch works as normal and it's ALOT cooler under there.

salad

Really? Why do you say that? Everything replaced in the last couple years?

That's not "fine". Once you get going the gauge should be at the 1/2 mark. Always! The only exception in these vehicles is if it's -40 outside. Either your temp sensor is lying or your thermostat is stuck open. What else in your cooling system is marginal?

The big effect of this is that your transmission won't lock up very often. Aside from using a lot more gas the AW4 is going to make a LOT of heat.

Sounds like you could benefit from an auxilliary transmission cooler and an overhaul of your cooling system, maybe with the ZJ clutch. On-demand aux fan is a good idea.

As for your original question, IMO vents look much less tacky than muscle car scoops and decapitate-me-please hoods lol

JeepaholicNinja

I agree with trying spacers on the back of the hood before making the next move

Atmos

have you ever crashed one of these things? trust me. that hood ain't going nowhere

SteveMongr

I also lifted the rear of hood with simple 1/4" spacers and longer bolts. Did not like looking at a potential guillotine so I dropped it back down.
'Run Cool' makes the best louvers. The stamping process leaves a raised lip on flat of louver openings, this redirects rainwater around it. All sizes and styles available.
http://www.hoodlouvers.com/product-c...ershood-vents/