Here's a pair of rarities that the person who posted this video to YouTube says were produced by Hanna-Barbera. So far, as far as I know, that hasn't been fully proven.
Lion Oil is a regional company originally out of Arkansas, but now based in Tennessee after a corporate merger or three. In the 2nd of the 2 ads, a Frenchman (reputedly Alan Reed) brings his sputtering sports car (Mel Blanc, of course) to a Lion service station, where the Lion himself (Shepard Menken) convinces him to try his brand of oil.
Bardahl is the better known of the two brands, and was founded by a Norwegian immigrant. The spot that opens the video features a quartet of gangsters inside an engine, whose plans are flushed by Bardahl (Gary Owens).
If anyone has more information on these ads, please feel free to pass it along.