Cold air coming in from the roof/headliner area?

[Pat Martone]

I live in New England and enjoy driving my Model A in the winter, prior to our roads being covered with salt, sand, and snow. (BTW - I am really impressed at how well my car runs in 30-40 degree weather.)

I have a '31 Slant Window Fordor with an Autolite heater set-up, but my car's interior is still cold, even with the tremendous amount of heat coming from the Autolite. It seems the car really never warms-up even though you can melt your shoe sole if it touches the heater vent on the firewall. Again, when the car is in motion, there is a great amount of heat being thrown into the car with the Autolite. However, there is simply way too much heat "loss" in the cabin area for the heater to "keep-up".

Specifically, I feel a draft of cold air coming from somewhere above my head when driving the car, and I think somehow I am losing heat through the roof or getting a draft from the outside into the roof/headliner area.

My rubber/vinyl roof is relatively new, in great condition and does not leak, even in the heaviest rain, but I somehow feel cold air movement overhead when the car moving. My headliner is not in the best condition and I was wondering if insulating the roof area in between the roof bows with a thin layer of fiberglass insulation prior to installing a new headliner might help minimize the cold draft that I now feel?

Any advice is welcome.

Thanks.

[Aerocraft]

I suggest that the draft problem very well may be leakage around the windshield. To verify the source, you could cover the windshield "joints" on the outside with a tape that will not pull paint when removed. I have used the "blue" tape which is used in home interior painting.

I have an Autolite heater in my 155A Town sedan which has a tight windshield and even the back seat is comfortable unless it gets reall cold. I generally drive with the drivers window open to regulate the heat in the front seat.

Gar Williams

[grapp]

Pat's advice is worth checking out. It would be hard to sneak insulation in from the underneath as you should have "chicken" wire holding up the padding. I would suspect that if it is not the windshield, whoever put the top on didn't add enough padding.

[Marco Tahtaras]

Cold air will swirl around the cabin under the circumstances described which makes it difficult to locate the source or sources unless you have a passenger feeling for it while you're driving.

As noted the windshield is a good place to look for starters. Also, most folks don't get a proper seal on the door windlace which is critical for staying warm. Be sure you have a properly installed rubber weatherstrip along the bottom of each door.

[Barry B./ Ma.]

Is the rear floor under the back seat sealed off? Road wind can blow up through holes under the back seat and travel up by the back window into the headliner.

[MikeK]

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One modern way to find air leaks, whistles, lifting vinyl and vibrating, buzzing trim is with a leaf blower pointing straight back (simulating headwind). Run it around the windshield, doors, and other body joints. Keep it pointing rearward! Like a pinpoint wind tunnel. I suppose you could do it with a compressor, too, but you would need beaucoup CFM's to get 60+ mph @ one foot from the nozzle.

[Pat Martone]

Thanks for the tips.
I have previously plugged all holes that I could find under the seats, carpet, foot pedals, floorboards, and firewall.
Since my car has no leaks in heavy rain, I assume there are no windshield leaks.
I wonder if insulating the inside roof (in between the wooden bows) before replacing the headliner (which has two quarter-size holes in it), will kill the draft and keep the car warmer? The movement of cold air inside my car is most noticeable at the driver head height. I think I can feel at least some cold air coming from the holes in the headliner.

[Marco Tahtaras]

Originally Posted by Pat Martone

Thanks for the tips.
I have previously plugged all holes that I could find under the seats, carpet, foot pedals, floorboards, and firewall.
Since my car has no leaks in heavy rain, I assume there are no windshield leaks.
I wonder if insulating the inside roof (in between the wooden bows) before replacing the headliner (which has two quarter-size holes in it), will kill the draft and keep the car warmer? The movement of cold air inside my car is most noticeable at the driver head height. I think I can feel at least some cold air coming from the holes in the headliner.

I'm not 100% sure but think the S/W Fordors have a drain trough at the upper rear corners of the top and running down the two rear body seams. If I'm correct (and you've driven it in the rain enough) that is the ONLY place you could get water leaking without seeing it which means the only place from the top you could pick up air. With that said, I don't believe that could produce enough airflow to produce what you describe.

I know these cars and air flow better than most so I strongly suggest you don't disregard suggestions because you believe you've covered those bases. As I said in my first post "Cold air will swirl around the cabin under the circumstances described which makes it difficult to locate the source or sources..." That means it can come from the lower rear and hit you in the face from the front!
You said you "plugged holes" but didn't directly address Barry (#5), so do you have a rear cross member COVER under the rear seat cushion? An issue there will do just as he described.

[Pat Martone]

Marco,
Thanks for your two informative replies.
What is a rear cross member cover?
I removed my rear seat cushion when installing an LED brake light on the rear window and had to drill a small hole in the steel floor to pass the wire. I don't recall seeing any holes there, but I will check again. I did see some kind of heavy cloth type material sandwiched between the underbody and some kind of steel pan covering the rear spring.

[Charles Coe]

My car has the drain trough at the top of the rear body seams as Marco described and what appear to be drain holes where the seams come down to the floor. It doesn't look like much air could get in that way. The cover over the rear frame was something like top material fastened to the floor with metal strips.

[Pat Martone]

Charles,
Now I recall, that's exactly what I have, top-type material with aluminum strips.
So now I still don't know where the cold breeze is coming from.

[Marco Tahtaras]

Originally Posted by Pat Martone

Charles,
Now I recall, that's exactly what I have, top-type material with aluminum strips.
So now I still don't know where the cold breeze is coming from.

You still need help chasing airflow around the doors and maybe beyond.

[Pat Martone]

OK, thanks, Marco (and other responders).
I will investigate further.