Automotive enthusiasts and historians--radioactive metals in motor oil?

Lately I’ve taken to streaming old time radio, usually mystery or detective shows, and in many cases the content includes the commercials that were included when the stories were originally aired. I usually do this to relax before falling asleep, and as a result, on one occasion, I woke up to hear only the last part of a commercial for some automotive product which I assume was engine oil.

According to the announcer, apparently, there was supposed to be some radioactive component in motor oil. So to demonstrate the superiority of this brand of oil, they used a Geiger counter to show that after thousands of miles of driving it would still generate a loud and vigorous amount of radioactive ticking. By contrast, the competitor’s brand caused only feeble ticking. The time frame would have been the late 1940s or early 50s.

Did I dream this, or does this actually make sense to anyone?

I’ve heard those ads in OTR shows.

Can’t recall what or when the ads were from, but what it was referring to was a test the company made to determine wear in engines. As I recall it was the competitors brand that caused the most ticking - the engine block was irradiated and higher wear resulted in more radioactive metal particles detected in the oil.

They used to make radioactive spark plugs.
The idea was the radioactivity would ionize the immediate area in and around the spark plug gap, promoting flame front combustion.