Hood Vents - my own personal test: engine bay temperature stats

[RZ.]

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[Old Jeeper]

I keep reading about the Gladiator grills being different yet every one I’ve seen is exactly like the grill on my 2021 Rubicon, what am I missing?

I forgot exactly, but they are different and I think its only on the ones with Max Tow and Rubicons, Moab that have the same towing ability, it lets more air in. I don't know if its still being done for the 2021s???

 

[zouch]

if you have the Trail Cam, your JL will likely have the same large-mesh grille as the JTs.

My ‘21 Rubicon has the exact same grill as that white Gladiator

 

[gato]

It is not currently overheating. The use case to date is spirited driving on the street in the summer. No off-roading, as I have not had it very long.

In my limited use, I have seen coolant temps around 230 and Engine oil temps as high as 275. This is new temperature territory for me. I come from the land of GM LS engines where coolant temperatures rarely got over 200 unless I was pushing the car on the track.

What concerns me most is the 275 oil temp I noticed during street driving. Those that track their Challengers typically only see those kind of temperatures on hot days after a 30 minute session.

Hopefully in the long run it will not be an issue and the engineers have done their due diligence, however, I am actively looking for things that can be done to reduce temperatures without voiding the warranty.

Got it. Yes, 275 is a bit high for street driving. I don't hit that on my LT1 Camaro 1LE even on track, though my C7 hit 300 easily on track.

If oil temps are getting that hot on the street, more airflow won't bring it down - you are in aftermarket oil cooler territory.

I'd just keep an eye on it and enjoy the vehicle. Keep the oil temp in the display.

 

[Lambert]

Got it. Yes, 275 is a bit high for street driving. I don't hit that on my LT1 Camaro 1LE even on track, though my C7 hit 300 easily on track.

If oil temps are getting that hot on the street, more airflow won't bring it down - you are in aftermarket oil cooler territory.

I'd just keep an eye on it and enjoy the vehicle. Keep the oil temp in the display.

Um… Yes. We have covered that already. I think the point was we need a greater differential pressure across the heat exchanger to help bring it down. The C7 has issues of its own for certain. I believe there are even lawsuits related to failed C7 Z06 cooling. Is your C7 a Z06?

I certainly will keep an eye, but It does appear to be an engineering failure. Hopefully Jeep monitors these threads and fixes an issue which has been observed by more than just myself.

I am (fairly) certain the hydroguide steel hood is not helping matters. The thing generates so much positive pressure under the hood it whistles at speed on the expressway.

Yes, I could solve it with an oil cooler but I would prefer a solution that will not void the warranty.

 

[Vinman]

if you have the Trail Cam, your JL will likely have the same large-mesh grille as the JTs.

I do have the trail cam.

 

[gato]

Um… Yes. We have covered that already. I think the point was we need a greater differential pressure across the heat exchanger to help bring it down. The C7 has issues of its own for certain. I believe there are even lawsuits related to failed C7 Z06 cooling. Is your C7 a Z06?

C7-Z51 (not Z06) I could do 3-5 hot laps before the tranny and engine oil got to 300 and the computers started flashing warnings and pulling power. Loved the car, but I track often and it was not fun. Camaro 1LE same engine never had a problem - that huge, ugly front, 13 separate heat exchangers, made sure it always ran cool. Once reason I haven't sold it yet. That thing it bullet proof on track. Even the alignment held for 3 years of tracking.

Anyway - back to your 392. 275F will not harm anything. If it doesn't go above that, just let it be.

 

[wcjeep]

Your factory cooling system seems adequate at speed. On my YJ, Poison Spyder hood vents made a large difference on the trail. In addition to more power on the trail I now occasionally use the heater. Previously without hood vents the cab stayed warm without the heater. With vents the cab is not constantly warm.

 

[Betty2020]

I recently purchased these hood scoops from OTB and they work great! I really like the fact they still drain the water in the factory location.
JL/JT Hood Vents - Iron Rock Off Road

 

[Steph1]

I recently installed a RR snorkel and to do so, you have to remove a molded foam part.

These molded foam things are located on both sides of the Jeep. Once removed, 1. They create a gap that lets air escape out between the hood and cowl, but 2. it leaves a gapping hole that leads inside the cowl. So I believe that if there was a grill in the side cowl, it would definitely let hot air escape from under the hood.

I might remove the left side foam part and reinstall when preparing the Jeep for winter. Cause it gets so darn cold here, that you need the heat in the winter months.

 

[ChuckQue]

I’ve asked this question a couple of times before with no responses, but, for low speed driving/trail driving, has anyone figured out a way to put in an e-fan override switch? I know the Tazer can be used to do it, but for those of us who may not be running a Tazer surely there is a way to put in an override switch? I realize the electrical and computer systems in these are much more advanced and sensitive compared to my ‘01 XJ, but I know having an override switch on it was a huge help when crawling.

Secondly, has anyone tried swapping out the e-fan for a higher CFM SPAL? I also saw mentioned earlier there isn’t any baffling around the radiator that keeps airflow directed through the radiator rather than allowing it to flow around it to a degree. I feel like if the airflow was directed solely through the radiator that would help immensely both at high/low speeds.

 

[dcmdon]

I installed the S&B Air Hood Scoops on my JL just last week. Too early to know if they make any difference under the hood, but we off-road in the Southern California desert often so we figured it couldn't hurt. Install was quick and easy and they look really good.

So now we get into different scoops and vents for different purposes.

Scoops like that could increase under-hood pressure which would decrease the pressure differential across the radiator which would decrease air flow across the radiator which could increase coolant temps at speed.

Though it would reduce under hood temps.

So what is your goal?

If you own a diesel and are looking for something that will help you pull up that mountain without the engine derating, this would be a TERRIBLE idea.

If you are rock crawling and want something to lower under hood temps, it could be a good idea.

 

[zouch]

has anyone had a problem with higher temps at low speed?
all i remember seeing complaints about in the JLD were when towing, and/or at speed. in ours, i've never seen the temps rise at all except under load at speed; crawling or creeping in traffic it's like it's barely even awake.

i suspect the largest part of the solution is going to be just like in our XJs; a better radiator.
after fussing with t'stats, t'stat housings, and liquid-to-liquid oil coolers (which all helped) all problems in the XJ went away with a good aluminum radiator. now the thing almost doesn't run warm enough!

I’ve asked this question a couple of times before with no responses, but, for low speed driving/trail driving, has anyone figured out a way to put in an e-fan override switch? I know the Tazer can be used to do it, but for those of us who may not be running a Tazer surely there is a way to put in an override switch? I realize the electrical and computer systems in these are much more advanced and sensitive compared to my ‘01 XJ, but I know having an override switch on it was a huge help when crawling.

Secondly, has anyone tried swapping out the e-fan for a higher CFM SPAL? I also saw mentioned earlier there isn’t any baffling around the radiator that keeps airflow directed through the radiator rather than allowing it to flow around it to a degree. I feel like if the airflow was directed solely through the radiator that would help immensely both at high/low speeds.

 

[OG Shark]

To make hood vents effective the outflow from the radiator really needs to be ducted out to the vents. Keeping it from escaping helps slow the build up of the hot air in the bay by guding that air straight out through the vent. Unfortunately with most modern vehicles there is not near enough room to properly do this without major modifications being done to make room for the chimneys (move the engine back, tilt radiator top forward, etc). We are working this setup into one of our race car builds right now - definitely effective when you have the room (or can create the room). Otherwise the vents are really just going to help relieve some pressure in the engine bay. Not something that will generally do anything at normal Jeep speeds (but if it does bully to you - send it!).

 

[ChuckQue]

has anyone had a problem with higher temps at low speed?
all i remember seeing complaints about in the JLD were when towing, and/or at speed. in ours, i've never seen the temps rise at all except under load at speed; crawling or creeping in traffic it's like it's barely even awake.

i suspect the largest part of the solution is going to be just like in our XJs; a better radiator.
after fussing with t'stats, t'stat housings, and liquid-to-liquid oil coolers (which all helped) all problems in the XJ went away with a good aluminum radiator. now the thing almost doesn't run warm enough!

I concur, I want to say the majority of JLUD cooling complaints were people hauling ass up grades and often towing while running larger tires without re gearing. I feel like I did see a couple people crawling that saw higher oil temps? Maybe?

I don’t know. I want to see how mine does when I get it. I’m also curious to see how @Ratbert does when he pulls his trailer since he’s a heavy ass AEV build on 37’s but with gears done as well.

I figure if it can handle hauling ass up the grapevine out of LA in summer I’ll be fine anywhere else

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