Just an idea how to cool under the hood
02-02-2010, 11:18 AM
#1
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Just an idea how to cool under the hood
So I was outside putting my K&N in and started to look at the rear hood weather seal and I got a idea. Our rear hood weather seal would come off and on easily, I even removed part of it. Now with the weather seal off it would create a gap ( almost the whole length of the hood) with the hood closed and is far enough up under the hood to not even be noticeable, the rear of the hood hangs over a lot from where the weather seal is located.
So the big question is would this gap create a cowl like effect to draw more air through the engine compartment and let heat out? I mean it seems like a such a simple idea and so easy to do. Get caught in rain, pull in to gas station, swap the strip back in, 3 minutes fixed.
Ok just went back outside and took off the rear hood weather seal, took a whole 20 seconds, there are 2 T clips to hold the seal in place, one each of the ends and then the rest of the seal is held by little L brackets molded into the cowl, it just slides off those. I've got some running around to do today, so I'm gonna see how it goes.
So the big question is would this gap create a cowl like effect to draw more air through the engine compartment and let heat out? I mean it seems like a such a simple idea and so easy to do. Get caught in rain, pull in to gas station, swap the strip back in, 3 minutes fixed.
Ok just went back outside and took off the rear hood weather seal, took a whole 20 seconds, there are 2 T clips to hold the seal in place, one each of the ends and then the rest of the seal is held by little L brackets molded into the cowl, it just slides off those. I've got some running around to do today, so I'm gonna see how it goes.
Last edited by HHRSSouth; 02-02-2010 at 02:05 PM.
02-02-2010, 12:08 PM
#3
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Really, wow, must be some good air flow up through there. I wouldn't have thought there would be enough air forced up through there to cause the hood to flex.
Did you take off all the hood weather seal or just the back piece and leave the sides when you did yours?
Also I noticed my hood could move up and down from the factory closed all the way, had about 1/16" of movement up and down (when I first got the HHR). So I moved the hood latch and re-tightened a smudge, no movement at all now. I could see if the hood was loose (like mine was) to begin with could look like its flexing up and down with air flowing through there.
Did you take off all the hood weather seal or just the back piece and leave the sides when you did yours?
Also I noticed my hood could move up and down from the factory closed all the way, had about 1/16" of movement up and down (when I first got the HHR). So I moved the hood latch and re-tightened a smudge, no movement at all now. I could see if the hood was loose (like mine was) to begin with could look like its flexing up and down with air flowing through there.
02-02-2010, 01:48 PM
#4
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Now for my real world results, I just got back from a 30 mile round trip (had to take my daughter to get some shots).
I took the highway on the way to my daughter's doctor going roughly 70 mph, the hood didn't move a smidgen.
On the way home I took the interstate and was cruising at 80-85 mph, still no hood movement.
I will try faster some time when I'm by myself.
My results were different from ScreaminBlkSS, but I did re-adjust my hood when I first had the HHR SS so it didn't move as previously posted in post #3.
I'm gonna keep my weather seal off, unless its steady raining or I start to notice hood deflection. It sure can't hurt having that strip off to let some of that heat out of the engine bay.
I took the highway on the way to my daughter's doctor going roughly 70 mph, the hood didn't move a smidgen.
On the way home I took the interstate and was cruising at 80-85 mph, still no hood movement.
I will try faster some time when I'm by myself.
My results were different from ScreaminBlkSS, but I did re-adjust my hood when I first had the HHR SS so it didn't move as previously posted in post #3.
I'm gonna keep my weather seal off, unless its steady raining or I start to notice hood deflection. It sure can't hurt having that strip off to let some of that heat out of the engine bay.
02-02-2010, 07:14 PM
#5
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Location: SE Michigan
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IMHO, that seal prevents water from draining into the engine compartment at car washes and when the vehicle is at rest. Sounds like a good idea, would be better with underhood temp readings, seal on versus seal off.
02-02-2010, 09:05 PM
#7
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Location: Washington State, where it rains
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Watch out for eng fumes coming into drivers compartment..not sure which way the air would flow but not good to have it dragging eng dirt across the windshield... and if it sucks in take note how it affects the cabin air flow...
02-02-2010, 09:11 PM
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02-03-2010, 01:19 PM
#9
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More testing done today on the rear hood seal removal.
I wasn't sure if the removing the seal was resulting in sucking or venting air, so today I did the strand test.
I took 4 strands of plastic (from a old pom pom my daughter had) and taped them to the edge of the hood closest to the windshield. Each strand was roughly 4" long, over hanging.
With the car warmed up and idling I could already see the strand moving slightly and feel the heat escaping from under the hood.
I ran 2 tests, I went through town, down the highway and out on to the interstate and back home (twice). My results were the same each time.
Idle: No major movement either way as far as air flow goes but you could see the plastics strands slightly move as the heat was escaping from under the hood.
0-15 mph the air is actually sucking into the engine bay, but......
15-95 mph the air is venting out of the engine bay, blowing out the back of the hood. (No hood movement at 95 I must add).
50 degree day here:
At idle my coolant temp was at 194 (this was after aggressive driving and the return trips both times, I let the car sit for 5 mins). You can really feel the heat venting out at idle after getting her warmed up good aka aggressive driving.
Through town (stop and go traffic) and down the highway (50-55mph) my average coolant temp reading was 187 degrees.
On the interstate cruising my engine temps dropped to 183 degrees.
And of course the faster I went the cooler the air was (common sense here).
My next test when it gets warmer out is to put the seal back on and compare the coolant temperatures to having the seals off on the same day.
I wasn't sure if the removing the seal was resulting in sucking or venting air, so today I did the strand test.
I took 4 strands of plastic (from a old pom pom my daughter had) and taped them to the edge of the hood closest to the windshield. Each strand was roughly 4" long, over hanging.
With the car warmed up and idling I could already see the strand moving slightly and feel the heat escaping from under the hood.
I ran 2 tests, I went through town, down the highway and out on to the interstate and back home (twice). My results were the same each time.
Idle: No major movement either way as far as air flow goes but you could see the plastics strands slightly move as the heat was escaping from under the hood.
0-15 mph the air is actually sucking into the engine bay, but......
15-95 mph the air is venting out of the engine bay, blowing out the back of the hood. (No hood movement at 95 I must add).
50 degree day here:
At idle my coolant temp was at 194 (this was after aggressive driving and the return trips both times, I let the car sit for 5 mins). You can really feel the heat venting out at idle after getting her warmed up good aka aggressive driving.
Through town (stop and go traffic) and down the highway (50-55mph) my average coolant temp reading was 187 degrees.
On the interstate cruising my engine temps dropped to 183 degrees.
And of course the faster I went the cooler the air was (common sense here).
My next test when it gets warmer out is to put the seal back on and compare the coolant temperatures to having the seals off on the same day.