VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Defroster vents

Hello everyone.
Will 1940-1941 GMC truck defroster vents fit on a 1940 Master Deluxe Sport Sedan?

Thanks,
Curt

Is there a major difference between a 40 truck or car with these vents? Does anyone have any sitting around off a 1940 Chevy MDSS they could post a photo of with measurements?
Any help would be appreciated.
Thanks,
Curt

Well I took a chance and bought a pair from eBay. I had the seller measure the vents and he verified they came from a 1940 car. They look to be in great condition. I hope they work!
Curt

Let me know if the vents you bought do not work. I probably have a spare set that I can either verify for you or sell to you.

dtm

Thanks dtm.
I'll let you know how they fit. This MDSS never had a defroster unit installed. This vehicle has an Arvin heater unit (looks great and works fine). Since I don't have the defroster blower and hoses, I'll have to rig something up to run hoses from the vents to the Arvin heater. This vehicle also has a Fulton 2 rubber bladed electric steering column fan. I'm in need of 2 rubber blades (may have to make my own). I just purchased an excellent electric NOS Westclox clock to mount in the glove box. One of these days, a radio would be nice! Just getting things while they're getable.

Curt

Does your Arvin heater have places to attach defrost hoses to,I think the Arvin heater that was in my 37 did.

I believe so. In the back side of the Arvin heater are 2 square shaped air outlets. One on the right and one on the left. I'll fabricate a square thingamajig that will accept a round hose. Although I live in Louisiana (about 110 heat index today) it gets very cold here and I remember how the 40 would really fog up. Anyway, I've got my eye out for a complete defrost system.
Curt

I think the one I have has two round ducts but could be thinking about another heater I have that came out of a 39 Plymouth,those of you who have a car are lucky since they are made to put defroster ducts in since there my 37 p/u was never designed to have them.

I received two excellent defrost vents from eBay that fit perfectly on my 40 MDSS.
One is just a little shorter and has a milder bend to it than the other. Would anyone know which one is for the left side or right side?

Thanks,
Curt

If you hold them in place it'll be obvious which is which. The angle of the inlet is to better connect to the defroster.

The hose connection side should point away from you toward the firewall and the approximately 45 degree bend is there to clear the wiper transmission arms. Correct? One vent has a little more than 45 degree bend and is about 1 inch longer on the hose connection end. It's this little difference that has me scratching my head. Since I don't have my dash or new glove box installed I'm being premature asking this question!
It'll make sense when everything is assembled.

Thanks Tiny,

Curt

I have several NOS Arvin heater defroster hose metal vents that attach to the heater. I am not sure which heater you have or if some of these vents will attach to your heater.

don3955chevy@sbcglobal.net

I'd be interested in 2 of those fittings. My Arvin heater is the one that has about 1.5 inch square ducts that stick out on the bottom rear right and left side. The front of the heater has the lighted red knob and the good lucking Art Deco front. To me, the heater unit looks like the entrance to those old theaters back in the day. If you put in a eBay search, vintage Arvin car heater, you'll see one there. I think several are listed and a few have some good photos of those square air ducts on the bottom rear left/right side.

Here is an eBay item number that is just like my heater:

331613703915

Thanks,
Curt

None of the ducts I have look like they would fit your heater. Are the square ducts on the side where the defroster hoses attach? The ducts that I have, have the defroster hose openings side by side and they are designed to attach to a single opening on the heater.I have several types and the ones I am referring to are marked 1940-55 DPCD. The only way they would work is to cut a hole in the top of the heater and attach the ducts. I don't think you would want to do that.

I hope I don't lead you down the 'path' but I believe my outlets were marked. If I remember right (it's been several years and I've slept a few times since) one of mine had an "L" stamped on it which went on the driver's side. As I noted above, once I got under the dash and held them in place it was obvious which went where.

Good morning Tiny.
I looked everywhere for a L or R stamp but didn't see any.
I'll figure it out once I get everything permanently installed.
As you implied, after the glove box and instrument cluster are installed, it will make it obvious where each one goes.
Thanks for your input and help.
:-)
Curt