H3 Working Hood Vent

[Chase Wright]

Does anyone know if there is a way to have an actual working hood vent?

 

[Bigunit]

Use the search function for "hood louver". Member paladine71 did this mod to his H3 and posted a thread about it.

 

[rsc]

http://www.hoodlouvers.com/hummer-h3/
Run Cool louvers. I have the smaller side mounted pair. I think they look the part. I can feel the heat coming out when stopped, but can also report that Run Cool's claims are a little exaggerated. They do work, as back to back IR camera photos show, just not as miraculously as the "50 degree" testimonials say to expect. (at least not at hwy speeds, I see little difference there)

The wife's H3-

My H3, same day, both about 5 minutes after shutdown from our hwy commute home-

 

[Mb30sdl]

Yes, mold lovers into your hood. Not a cheap solution.

 

[ReconH3]

Both Paladine 71 and I have converted the fake plastic hood louvre into a functioning one. Paladine's write is a lot more detailed, but here's mine. Starts at post #362.

http://www.hummer4x4offroad.com/forum/showpost.php?p=129534


"Ex Umbris Venimus"

 

[Ghostbuster]

So fab a hole right under the factory hood louver thing and stick one of these fans in there to pull air out. Then have some guy fab a custom air vent to go over it? Or just just slits in the oem cover?

http://www.a1electric.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=30100400

That's how I would do it I think... but... why fix what isn't broke..

 

[ReconH3]

So fab a hole right under the factory hood louver thing and stick one of these fans in there to pull air out. Then have some guy fab a custom air vent to go over it? Or just just slits in the oem cover?

http://www.a1electric.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=30100400

That's how I would do it I think... but... why fix what isn't broke..

It is broke. That's why it needs fixing. H3s are known for overheating, especially Alphas. No need for a custom vent. There's already many aluminum aftermarket ones that are functional. The cheaper option is to open up OEM one. I was going to do that until I found an aftermarket one already made. I don't think a large 16" fan would be optimal because the holes cut into the hood are two separate ones that are smaller. I would use two smaller fans like they use in computers. I haven't added the fans yet, but I do have a temp activated switch to turn them on when it hits 190. Even without the fans I can already see the heat coming out when stopped at a traffic light.


"Ex Umbris Venimus"

 

[benlaud87]

I still have to cut holes under my hood vent, I plan on doing mine like recon's.

 

[Ghostbuster]

It is broke. That's why it needs fixing. H3s are known for overheating, especially Alphas. No need for a custom vent. There's already many aluminum aftermarket ones that are functional. The cheaper option is to open up OEM one. I was going to do that until I found an aftermarket one already made. I don't think a large 16" fan would be optimal because the holes cut into the hood are two separate ones that are smaller. I would use two smaller fans like they use in computers. I haven't added the fans yet, but I do have a temp activated switch to turn them on when it hits 190. Even without the fans I can already see the heat coming out when stopped at a traffic light.


"Ex Umbris Venimus"

Gotcha. So easiest/cheapest way to go is take off plastic bit, cut vent holes in plastic bit, cut the two holes in the hood itself, mount two 140mm ish waterproof fans, and mount an on off switch of course.

edit: I didn't know they had overheating issues. I thought only if the radiator or something else failed like a temp sensor..

 

[benlaud87]

I wouldn't say that's the easiest. It can be tough to cut straight lines in plastic. If you're good with a dremel it shouldn't be too hard but if you've never used one you might want to practice first. It would be the cheapest way though.

 

[ReconH3]

More than cutting slits, since its hard to get perfectly straight, I would drill a series of holes. That would also help maintain integrity of plastic.


"Ex Umbris Venimus"

 

[Best4x4]

My Alpha runs cooler than my 3.7L!

 

[benlaud87]

True, id probably use a cutoff wheel and make a series of slits. Mostly because I would start getting sloppy after drilling 100+ holes. I'm glad I found the metal one on eBay so I don't have to put myself through that.

 

[ReconH3]

I got mine real cheap directly from manufacturer since I asked for one in the rough so I could finish and paint it myself. They usually are expensive due to all the polishing and chrome.


"Ex Umbris Venimus"

 

[SuperBuickGuy]

I had an issue where my Alpha got warm a day or so ago, and now I'm considering my options. I'm still reluctant to cut holes in the hood because I used to have a 4x4 V8 s-10 blazer with a louvered hood. It never overheated - but I always had an oily film on my windshield. I guess there was a slight benefit, though, I could tell when something was going wrong because I could smell the motor because the vapors and such would go into the cowl... and into the car.

On my Corvette, I opened up the side vents; and I have no overheating problems at all... I'm thinking that might be a choice for the H3... open up the fake air intakes. Air acts like water - it takes the path of least resistance, so putting vents in the side would allow hot air out of the engine compartment... I could even put fans to draw the air out better...
*thinking outloud* thoughts?

 

[SedonaBound]

I don't think I'd do for functionality. Moving more air through the hood is only going to have a marginal effect. The only way to improve cooling significantly is a more efficient radiator. The cosmetic hood panel is only there to imitate the military HMMWV's functional hood louvers for its steeply slanted radiator. If it was effective on the H3, GM would have put louvers in the hood die and saved the $ for the fake louver panel. I know they test for adequate airflow through the radiator/engine bay.

 

[Best4x4]

I agree louvers aren't going to make up for our H3's tiny radiator, but at the same time venting the hood isn't a bad thing. If I could find someone to make me a good thick black hood sticker, I'd remove the fake louver all together! And just put two small metal louvers in the center of that.

If GM hadn't put the fake louver on people would have probably bitched about it. I think the curve of the hood with just a flat black sticker in place of the fake plastic water trapping louver would have been just as effective.

I'm all for a good working louver setup on our H3's but the I5's already had issues with water and the leaky fake louver. Installing an actual working louver is going to make that much much worse on the I5. The Alpha's 5.3L has the large engine cover and the coils are pretty protected.

 

[rsc]

I know I have cracks in my exhaust manifold, that probably doesn't help with under-hood temps although I don't know how much that affects the engine/radiator temps. I wonder how many others with temp problems have exhaust manifolds putting hot air into the engine bay?

 

[SuperBuickGuy]

I don't think I'd do for functionality. Moving more air through the hood is only going to have a marginal effect. The only way to improve cooling significantly is a more efficient radiator. The cosmetic hood panel is only there to imitate the military HMMWV's functional hood louvers for its steeply slanted radiator. If it was effective on the H3, GM would have put louvers in the hood die and saved the $ for the fake louver panel. I know they test for adequate airflow through the radiator/engine bay.

I'm not sure I'd believe that with GM... louvers are a custom item for very good reason (C7 excepted), there are as many downsides as there are benefits. the trick is still to get the air out, in is easy...

I know I have cracks in my exhaust manifold, that probably doesn't help with under-hood temps although I don't know how much that affects the engine/radiator temps. I wonder how many others with temp problems have exhaust manifolds putting hot air into the engine bay?

up to 700 degree air inside a closed engine compartment is almost guaranteed to cause overheating issues, and seal issues, and valve cover issues, and emissions issues, and fuel economy issues...

 

[Panzer07]

I seriously don't see how everyone is having over heating problems here, and it's been beeshting hot here lately 95-110 temperatures...my truck's temperature gauge runs 1/2, and that's only when cruising at highway speed of over 70-75 and that with 35's. And I have no engine tunes or upgrades, only time I did had a problem was when going up the mountains of Colorado. and that was with a full truck, and trying to keep the speed at 65, that was the only time my temperature went up to 3/4. As in regular commuting the temperature gauge stays at 1/4 even in this hell like temperatures. But that's just my case. I'm thinking in doing the working hood vent mod just mainly for looks as well to let some of the hot air out, but I want to use one of the H1 hood vents, only thing stoping me is the $400 and something price for it, which I don't quite justify it.
Just my 2 cents.


Sent From Someone Else's iPhone 'Cause I'm Too Broke To Own One.

 

[ReconH3]

If you don't have any heating issues, then you're lucky and this thread is not for you. For those of us that do have this problem, it's a serious matter that has to be dealt with, and this is one of the solutions. With overheating, it's never one thing that solves it, but a series of different solutions.


"Ex Umbris Venimus"

 

[Best4x4]

Yep the humidity down here in SETX doesn't help. Back to OEM fan clutch vs efan has made a drastic improvement. But the hot air trapped under the hood has got to go!

 

[SedonaBound]

I'm not sure I'd believe that with GM... louvers are a custom item for very good reason (C7 excepted), there are as many downsides as there are benefits. the trick is still to get the air out, in is easy...

I only say it because back in the 90s when I was visiting my old digs at U of Mich, I saw the front end of a GMC truck, engine and all, undergoing flow analysis in the ship model test tank.

 

[rsc]

I wonder if I could find the space somewhere for a small, secondary radiato or oil cooler...

 

[JonBishop]

I did a quick write up on a how make the cheap easy hood louver mod using the OEM louver, all u need is a angle grinder, and some time and u can do it, not to hard, jus look up "cheap mans hood louver mod"


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