Good call CMD !
Here's a similar one with this comment added: "It looks like a disc wheel spare tire mount emblem to me. That would be about '22-'26. They are being reproduced." http://forums.aaca.org/f170/dodge-br...em-222123.html
Don.......
There is a lot of history regarding the Dodge Brothers on Google. The three links below are just a sample. A radiator "emblem" is different than a radiatior "cap." The last picture below illustrates the difference, and shows one of their emblems on a 1920 Speedster. I haven't researched it enough to determine what years your particular emblem was used, but with a little more research it shouldn't be too difficult to narrow down. However, it seems that the majority of the Dodge Brothers emblems had the Star of David on them.
SBB
History Links: The last one has some cool pictures ...
Based on some additional, but brief research, my best guesstimate on the date of your emblem places it sometime between about 1915 and 1928. (Inconclusive).
SBB
Founded as the Dodge Brothers Company in 1900 to supply parts and assemblies for Detroit's growing auto industry, Dodge began making its own complete vehicles in 1915. The brand was sold to Chrysler Corporation in 1928.
They used a blue and white double triangle which resembled a Star of David up until the takeover by Chrysler in 1928.
The blue enameled emblem I posted a picture of earlier, which appears to be identical to yours, just popped up on one of the dozens of websites I was looking at regarding the Dodge Brothers. But the individual who posted the picture said "he didn't have any idea what year it was from."