What it this? Located on passenger side firewall. 1964 330

[McPorGuy]

What is this opening on the passenger side firewall? What is the function?

Firewall is flat on the inside of the car with no openings. The "bulge" in the engine compartment firewall is covered by this newer looking rubber flap.

Thanks for your help.

 

[Dutchrebuild]

Cowl drain

 

[snakeoil24]

air conditioning freon ports??

 

[lewtot184]

Water drain

 

[icetech]

Detroit musclecar makes new flaps for that if you ever need one

 

[493 Mike]

A piss poor design too! I filled the inner lip with fiberglass resin to raise the floor of the drain. There is another one of these on the right side behind the fender.
Mike

 

[Dave6T4]

They usually get plugged up with small leaves, pine needles, etc. and no longer drain. Then, the cowl starts to rot out.

 

[ckessel]

One of the many holes that got capped off on my 65.

 

[493 Mike]

I have posted on this area previously but, many may not have read my tale of woe. I had to remove the entire cowl piece to repair rust damage, and before reinstallation I lined the entire cowl bottom with fiberglass and resin for a waterproof repair. I used gloss black Rust O Leum enamel to topcoat the fiberglass. I was able to stuff cardboard thru the interior fresh air opening for paint masking to keep it dark inside.
Mike

 

[matthon]

Red arrow, right side cowl drain has a ridge at the bottom, and a rubber flap (no rubber flap in pic).
Remove rubber flap, and remove ridge if possible.
I had to replace the entire firewall.

 

[khryslerkid]

I always thought the flap was for releasing cabin pressure when closing a door. They still use them on new cars. It works like a one way valve.

The drain is what Matthon shows in post #10.

 

[matthon]

Front drain sucks too. Although it is higher than the drain at the far right side of the car (post #10 pic) it becomes very narrow inside the cowl, between the front drain hole and the inner cowl.

 

[493 Mike]

I always thought the flap was for releasing cabin pressure when closing a door. They still use them on new cars. It works like a one way valve.

The drain is what Matthon shows in post #10.

Both flaps are drains for the cowl slots (all connect to the inlet air chamber). If it was for air exhaust due to door compressing air in the interior it couldn't compete with the area of slots in the air inlet for air exhaustion.
Mike

 

[1STMP]

I always thought the flap was for releasing cabin pressure when closing a door. They still use them on new cars. It works like a one way valve.

The drain is what Matthon shows in post #10.

X2

 

[VANDAN]

What is this opening on the passenger side firewall? What is the function?

Firewall is flat on the inside of the car with no openings. The "bulge" in the engine compartment firewall is covered by this newer looking rubber flap.

Thanks for your help.

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Car looks Real Nice, and wiring says MW. Any more pics you'd like to share ? I've got it's "older & younger" brothers, in the same Triple Medium Turquoise Color scheme !