GKK

I'm considering trimming down the rubber hood cowl seal to vent the hot engine bay heat out. I think it would help the AC work more efficiently during these 105* days.

I would trim down leaving about 1/4" of the cowl seal and leave the area around the distributor alone.

Would this be an efficient way to vent the engine bay, because I see no other way of venting out the heat other than installing hood vents.

I know others have done it but, can't find the threads anymore. Thanks

GKK

I just remembered that the area between the windshield and rear of the hood is a low pressure zone and at speed, air will be sucked into the engine compartment similar to how a cowl induction hood functions.

Hot air will only escape from the engine bay when the vehicle is stopped.

I'll leave it alone for now and look for another solution.

Ramanstud

you're right, the hood/windshield area IS low pressure....

which is why opening up the seals in that area will help draw from the high pressure areas in front of the radiator and sweep over the motor and out the hood. There was a thread on this a year or two ago (maybe lost?) and I believe it did work quite well. It worked well enough to where some of us wondered why those seals are there in the first place! lol. You are on the right track in not removing the seals by the distributor - just in case.

By the way, a hi-rise hood works the same way (by allowing airflow out and over the windshield). Otherwise the only other way for air to move out efficiently is through the "gills" on the side and under the car by the exhaust.

Hotred94

I trimmed the hood seal about two years ago, or sections of it I should say. Some guys are pretty leary about cutting things, but I marked it out and cut it carefully so it looks almost factory cut. It has been somewhat effective but it really could use more vent area. Just an hour ago I drove the car and watched the heat waves coming out from under the hood. A lot comes out; after sitting for about half an hour the wiper arms are too hot to touch.

On mine, I trimmed on the passenger side from the end to the wiper lift stop (the wiper sits on it when it is turned off and drawn inside the hood. On the drivers side I trimmed from the end to the computer (1994 car, yours is probably different), left it alone around the computer so no water will ever get in there, then from the end of the computer I cut another 6 inches toward the engine. Left the middle area alone because the seal is not very tall there. I always left a 1/2 tall seal where ever I cut to keep the water out. Quarter inch tall made me nervious. Use a sharp razor knife and the rubber cuts like butter.

On the airflow, as tested on my car, from 0 to about 15 mph, air flows out from under the hood. From 15 on up air flows in.

GKK

Thanks for confirming what I suspected. I'm going to install hood louvers onto the hood when I paint the hood next year.

Da Mail Man

***an observation....if you cut the passenger side (weatherstripping) by the passenger side of the distributor, will not hot air be sucked into the a/c outside intake which is located somewhat in the wiper compartment and covered by "mesh" to keep debris out?

when you select from your a/c control panel to have outside air come into the car to be cooled, if you place your ear there, you'll hear "the suction of the fan intake of the a/c".

last, would not all that extreme heat accelerate the demise of the wiper blades?

RICEKILA

I cut my hood gasket ( except over the distributor) I also gots hood louvers. When I sit at a light I see heat waves exiting at the base of the windshield and the louvers), when I sit at a light when the rad. fan is on it looks like a blast furnace ( kinda). At speed air pressure at the windshield may/does push cool air in but at least its cool. But between the Z-51(ish) spoiler, Big Mouth Air Dam, hood louvers and the cut hood gasket she doesn't over heat ( so far) and is rock steady at speed ( 11.5 squared ) One of these days I'll find a way to get temp. readings from the louvers, hood gasket and side gills.

Aardwolf

It's cut on mine:



With a 180° 'stat mine cruises at 185° and oil 190° in hot and humid weather.

Da Mail Man

.......well, i guess that firmly establishes that warm/hot air IS sucked in through the outside air intake at the wiper compartment area when the occupants of the vehicle select "outside air" to be mixed with "cockpit" air to be cooled.

this would also stand true if the car was stationary OR in motion as reflected by draw of the outside air never "shutting down" while in said movement due to any changes in pressure and turbulence.

it also appears that since there is an actual draw or suction from the a/c blower fan mounted in the airbox, that with the a/c off and just outside air being selected (econo), that the air would be noticeably WARMER inside being blown out of the cockpit vents since there is that suction and draw that we have already established.

Hotred94

The way I cut my seal, only about half on each side, I have not had any problem with warm air being sucked into the cabin. I thought it would be a risk but most of the intake grill on mine is still behind full height uncut seal. I honestly have not noticed any influence on cabin air. Same with wiper rubber, most of it is still protected by full height seal; no problems.

GKK

From the pictures and observations given, the bottom line seems to be:

(1) The hood cowl seal is there to keep engine heat Away from the air intake vents to the interior.

(2) It also, keeps water from running down the firewall.

Hood Vents installed on a high pressure area on the hood and larger side vents would be a more effective solution. Thanks everyone.

Da Mail Man

C4DC

Just have to know that you will be sucking the hot air and fumes into the cowl intake vent for the AC. A friend did it and has since replaced it and did the hood vents.

Da Mail Man

......i think the only way you can get away with this would be to do an incision at the drivers side as there is no real induction of the a/c fan intake there.....