Join Date: Dec 2004
Location: East Wenatchee WA
I have been running the Gen-Right 5 piece black louver set for a while now. Tested differences over a 3 day install roughly to see what and how each set effected the rig overall as well as any heat dissipation from underhood. If you understand the purpose of the louvers, then yes, they work quite well. They most certainly lower underhood temps and by a fair amount by allowing underhood heat to escape out the vents rather than being trapped under the hood. Due to a clogged cat, heat under my hood was so bad, I couldn't touch the hood at all without gloves to even open it. After install, no issue without gloves. Sure it's still warm, but not hot and certainly not blistering hot like before.
Regarding the cooling system-these do NOTHING for your cooling system at all. The won't make the rig run any cooler, nor will they make it run any warmer. If your cooling system is up to par, there should be no change to it after install of the louvers. If there is, it's purely coincidental and you need to evaluate your cooling system to find what's on the fritz.
I have the factory insulation underhood on my '05 LJ. When I installed these, rather than remove it entirely, I simply cut through the insulation where the vents were, and left the remainder in tact. I've been in many HEAVY rain storms now since install, sometimes for hours on end. Also been in heavy snow for extended periods of time. To date, I have had NO issues with either water or snow with the louvers. There is enough heat coming out at a fast enough rate that it pushes the water/snow out before it has a chance to enter. I've always made it standard practice in heavy snow to wipe all the snow off the vehicle before driving away. Around here, you'll get a ticket if you don't clean the snow, and it's safer anyway so after I start it to warm it up, I scrape all the windows, wipe off the hood, lights/taillights, etc., then drive away. I can't comment on how leaving several inches of snow on the hood would effect it as I just don't do that. With common sense and sensible safety habits prior to driving, there should be no issues with the louvers or effects under the hood.
I have also washed the rig a few times (gasp!) prior to install of other mods or other work done. From the washing on a cold rig where no heat has been generated under the hood, I DO have some water marks on the insulation now. This has been from washing while cold and getting carried away with the hose spraying into the louvered areas. Only issues here are my insulation is discolored a bit now in those areas-no running condition issues or other problems to speak of.
Regarding destruction of paint concerns-the only real issue you'll have here is the cutting of the hood and what it will do to the paint. I used a grinder with cut off disc for my first cuts as I couldn't find the jigsaw. Worked well but was a pain and did remove much more paint that I'd cared for as it chipped off/flaked off in areas rather than simply cutting through. After the first cut out, I looked harder for the jig saw. It worked MUCH better than the grinder, left the paint relatively unharmed around the cut compared to the grinder. I did prime everything prior to final install of the louvers to eliminate rust issues. With the concern for heat dissipation ruining your paint-while I don't have real LONG term testing in terms of years of service, what I can say to this point since install is it's not a concern. There's close to 1/2" or more of mounting flange around the louver that protects the paint in that area. The shape/design of the louvers vents it out and as heat rises, it goes up, rather than baking the hood paint further out. I've seen no ill effects to date from heat escape. Now, trail damage from timber-that's another story...
I should note that I had never really cared for louvers prior to install. I was hesitant at first to do it, but due to severe underhood heat problems that were killing other underhood components from the clogged cat, I did them against my will while waiting for parts to show up for cat replacement. Since then and after running them now for a good while in all conditions, I've changed my tune. They've grown on me quite a bit actually and I kinda dig the look now. The definitely do what they're supposed to do, which is remove excess heat under the hood. The 5 piece kit makes the most noticeable difference, but each piece added does have it's own benefits within it's limitations of size. Obviously more area to vent will have the greater effect of reducing temps. Water was a BIG concern for me, but has proven to be a non-issue. Overall, I'm really happy with them-which is surprising as I didn't care for them prior to purchase/install. Yes, I'd recommend them if you need them. If it's for looks only-well, that's your deal, no comment on that.
Best of Luck,