Adding Hood Vents- Worth it?

[JimBill]

Considering adding hood vents to my WJ, in hopes of helping lower under hood temps and improving cooling when creeping. Has anyone added vents to your rig? Feedback from someone who actually has installed vents and has before and after experience would be great. The theory is pretty straightforward, but does the effort justify the result?

 

[Boostpowered]

First off are you overheating the engine, is it getting close to overheating? If so you should start changing thermostats, water pump etc.

Do you get alot of rain/snow? Everything under the hood will get wet alot if its a real vent

Do you cover your jeep or keep it parked in a garage or car port most of the time? This would help some with the wetness but also block uv rays from deteriorating hoses and wire shielding.

Vents will work better if you are continuously moving or windy conditions, idling or moving real slow in stagnate air, vents make a very small difference

Pulling the fender liners out of the front wells will likely render the same result as hood vents allowing more air to flow. Might want to do that before you cut up the hood and see if things get cooled

Are you lookin at the vents that are one big panel that replaces part of the hood or individual vents? Personally I'd go with the large panel and make another solid piece of sheet metal to put on the underside of the hood vent to block it off when raining or when I didnt really need it in use, or more expensive get a stock spare hood to swap out when needed

 

[MMc]

If you are getting hot there is something wrong, if you are hot see above. If you just are looking more air movement upgrade the fans. If you want to do vents right you need a shield under vents for water.

 

[rho]

Ive been thinking about a vented hood for my JKU for similar reasons, overheating isn't generally an issue with our rigs when crawling but prolonged high underhood temps often are.

My JKU is only 8yrs old, but it has almost 165k on it.. and most of that is stop/go commuting traffic and slow speed 4x4 stuff. Because of the low speed, reduced airflow and general warmness of CA, ALL the underhood plastic is fried, falling apart and the engine wire harness is starting to fail in places because of this too.

Not sure what rig the OP has, but if its a jeep, some hood vends can be added without too much trouble that will help the heat soak issues when the rig is turned off and long periods of driving in 4Low.

 

[JimBill]

Cooling system is fully replaced and changed to factory heavy duty configuration (hydraulic driven fan converted to factory electric plus mechanical clutch fan with upgraded fan). Attempted to use factory parts wherever possible to aid in parts availability for unexpected and/or remote repairs and for general reliability and compatability.

On torture testing temperature settles on either side of the 210F line. Not trying to cover a cooling issue, but wondering if overall cooling can be enhanced. I'd like to hold 205 max. And wow the heat soak on a 90 degree + day is insane. Can't be good for anything in the engine compartment. I like tuning, tweaking, and generally making small meaningful changes to aid in reliability and or capability. If anyone has experienced even a small benefit from the vents, then they may aid in reliability.

Engine gets dust and dirt now, do not see that as an issue. Snow is not a concern, and rarely travel to snow. Rainfall is 13 inches average, which means we either get 7 or 19 inches. It is parked outside. I don't see UV as a significant issue, as if I do this I will go with a louver panel on each side with likely little direct sun (as opposed to a screen). Water crossings are not a problem either, if I have water over the hood I have already hydro locked the engine.

Temps are moderate, but summers do get 100+ at times with a max at 123F one day a few years ago. Extremely rare, but I want to have the best chance of surviving extreme temps or when I suddenly find myself in stop and go at 111 degrees (it's happened.....).

Unibody construction, removing fender wells is not an option. In my younger years the budget minded hot rod guys would stack washers between the hood and hinge, to raise the back of the hood and allow heat to rise out. The rich guys would have the hood louvered. I'd just take out the cowl to hood seal and call it good. But all that mainly did was help reduce vapor lock, not so much a problem with pressurized closed fuel systems of today.

The junkyard hood approach is already on my mind, plenty to choose from at the local Pick and Pull. But unless there is someone who can say they saw a benefit, I am not likely to spend the time and money to give it a try. So I turn to you all for your experiences as I am curious.

 

[JimBill]

Ive been thinking about a vented hood for my JKU for similar reasons, overheating isn't generally an issue with our rigs when crawling but prolonged high underhood temps often are.

My JKU is only 8yrs old, but it has almost 165k on it.. and most of that is stop/go commuting traffic and slow speed 4x4 stuff. Because of the low speed, reduced airflow and general warmness of CA, ALL the underhood plastic is fried, falling apart and the engine wire harness is starting to fail in places because of this too.

Not sure what rig the OP has, but if its a jeep, some hood vends can be added without too much trouble that will help the heat soak issues when the rig is turned off and long periods of driving in 4Low.

Bingo! heat soak. All my plastic is as brittle as can be for all the same reasons. The rig I have is a WJ 4.7 V8. If placed right it will vent rising heat from the exhaust manifolds.

 

[rho]

Not gonna lie, I wish my JKU had a mechanical fan. I prefer them over full electric as they tend to keep more air moving through the engine bay in idle, traffic and low speed crawling stuff.

For the ZJ Grand Cherokees... I think the 5.9 ones had factory hood vents...

 

[EXPO_D1]

Not gonna lie, I wish my JKU had a mechanical fan. I prefer them over full electric as they tend to keep more air moving through the engine bay in idle, traffic and low speed crawling stuff.

For the ZJ Grand Cherokees... I think the 5.9 ones had factory hood vents...

they did have them on the 5.9l hoods. ive heard mixed results if they are effective or not

 

[JimBill]

First off are you overheating the engine, is it getting close to overheating? If so you should start changing thermostats, water pump etc.

Do you get alot of rain/snow? Everything under the hood will get wet alot if its a real vent

Do you cover your jeep or keep it parked in a garage or car port most of the time? This would help some with the wetness but also block uv rays from deteriorating hoses and wire shielding.

Vents will work better if you are continuously moving or windy conditions, idling or moving real slow in stagnate air, vents make a very small difference

Pulling the fender liners out of the front wells will likely render the same result as hood vents allowing more air to flow. Might want to do that before you cut up the hood and see if things get cooled

Are you lookin at the vents that are one big panel that replaces part of the hood or individual vents? Personally I'd go with the large panel and make another solid piece of sheet metal to put on the underside of the hood vent to block it off when raining or when I didnt really need it in use, or more expensive get a stock spare hood to swap out when needed

All good things to consider, thanks!

 

[Boostpowered]

Bingo! heat soak. All my plastic is as brittle as can be for all the same reasons. The rig I have is a WJ 4.7 V8. If placed right it will vent rising heat from the exhaust manifolds.

I don't think the brittle plastic and wiring are from heatsoak necessarily, more likely that year range or even the manufacturer used an inferior plastic mixture and used a soy based plastic for the shielding on the wires which hardens up over time and cracks. Wildlife find those soy wires tasty too.