Productmobiles...almost solved!

[Allemano]

The ad dates from 1934 and the car judging by the wheels could be a 1930 Maybach..

[Ray B.]

The wheels point in another direction, and so does a precise trademark of this make.

[Allemano]

I'm not an expert on this terrain. To me most of them look pretty much the same..
Let's invite others to make a more educated guess.

[pnegyesi]

I'd say it is an Adler, probably a Favorit

[guido66]

Fine!
At least you found my original source and it's usually worth one point.
I'll save the other for whoever gives us the chassis. A very slim chance for this, but we've seen it happen.

I've had these pictures sitting on my computer for months now. Never thought that posting the "originals" here would be worth a point 

[Ray B.]

Sorry about that, Guido. So did pnegyesi and Allemano, apparently, but they were faster.
And pnegyesi only replied because I had posted a reminder of this old puzzle, not because I had promised a point, which I didn't.
I eventually decided it was worth one because in such cases, when the picture comes from an old magazine, it usually gives an identification for the car. So the job is to find the source.

You can still earn your own point by finding the original car (I only ask the make and year, given 1 or 2).

@pnegyesi: not an Adler.

[Allemano]

Ray, do you have the right make for sure?

[Ray B.]

95% sure. The 5% being because it's not confirmed by the source, and the photo quality isn't topnotch. But I know these cars well and to me there's no mistake. I'll show examples.

[guido66]

Brennabor?

[Ray B.]

No. Look in another direction.

[Allemano]

German manufacturer?

[Ray B.]

Nope.

[Allemano]

Maybe a late twenties Buick? ('28 Master Six) The level line of the bonnet makes me think about this..

[Allemano]

a 1929 Cadillac is another possibility..

[Ray B.]

It cannot be a Cadillac, I'll explain why. And if a GM car, it sould be earlier than 1928, last year for the drumlike headlights.
But I had foreseen some strong resemblances of  Buicks with the puzzle car.  Yet I believe that my proposal is more correct. When you find it we'll declare this solved. Locked for you 48 hours.

[Ray B.]

All right. In the end I'll say that Allemano's guess, a Buick (but 1926-27) is even with mine (1927-28 Packard).
Let's get picky (paying no attention to what's behind the firewall and has been modified.
I proposed a Packard because they had an unmistakable hood shape. Seen from the front you have a rounded bulge in the center, then on both sides a flat part, maybe two inches wide. That flat part accounts for the protruding shape that you see on pictures taken from this angle.
Packard 1, Buick 0
Packard also had very commonly disc wheels with the same 6 bolts setup and an hexagonal red center.
Packard 2, Buick 0
But I realized that Buicks had an approaching hood shape, with a less wider flat part, before 1929 (Cadillacs never had that).
Packards were much more common with sidemounts, but some Buicks had them too.
Buicks almost never sported disc wheels, but they were optional. And they were less concave than the Packard's, as it seems to be in the puzzle car. They came with our without a red center, depending on images.
Packard 2, Buick 1
Last but not least, you often saw on these Buicks that protective plate below the door sill than you see on the puzzle car. I didn't see it on Packards.
Packard 2, Buick 2

And a point for Allemano.

[Allemano]

Now I'm still uncertain but think the edge of the cooler refers to a 1925/26 Packard. Probably something like that:

[Allemano]

Oh I see, you already made some own research..

[Allemano]

with protective plates..

[Ray B.]

Here is a 1926 Buick with protective plates that look more like it (as in my former Buick picture).  And disc wheels, 6 wheel nuts too,  that would look more like it unless... I hadn't seen these bolts on the outside rim!
Youre right, the radiator edge is much more Packard.  There can be endless discussion. We must never forget that, just like now, people changed things on cars.

75america 3 points (I gave up waiting for him to give us the model of the #6 Studebaker. It's a Dictator).
Allemano 2 points
Joaoa, Impishgrin, Guido66, pnegyesi 1 point

Points tallied. Still open for final ID of #7

[grobmotorix]

Productmobile #7 might have been built upon the chassis of an Opel 15/40 (built between 1927 and 1929).

[Allemano]

I think Grobmotorix could be right!



This is the Opel 12/50

They got that certain edge on the cooler as well:



And the bonnet looks exactly the same!

[Ray B.]

True about the hood, but the hood only: look at the wheel hubs and the fenders, front and rear. The wheels don't match well and the fenders have a vertical side slab (is this the right way to say it), that the puzzle car hasn't got at all.
It's not because we're in Germany that it's a german car. Packards and Buicks were abundant in Europe.

[Allemano]

I'm searching for some better pics, but still, I believe it could be an Opel.
Would be more likely in the city of Berlin..

On the Coffee Car the diameter of the circle described by the wheel nuts is still different from the Buick and Packard. The circle is at least wider on Opel wheels

[Ray B.]

I don't think you can't measure that with precision on such grainy pictures. Looks all the same to me.
Once again, I believe that we can discuss this endlessly. I'll point at two details that point, the first in a direction, the second in another
Here are two more pictures of Opels from your source (note that the smaller models have four nut wheels):
1-  What may indicate that Opel is the right answer is the space between the firewall and the windshield, shorter in the Opel and the puzzle car. But it may vary beween models of the same brand.
2- Look again at the fenders and check what I've said. Those on the puzzle car match the american cars' not the Opel's at all.
Let's admit that we're not sure.