This thing is still going?
GM frames, front subframes, engine cradles, control arms and sometimes other things were suspended from an overhead conveyor. As they approached a tank of Chassis Black the conveyor dipped down and submerged the part then rose out of the tank and traveled for several feet over a long drip pan that caught most of the drippings. But for many feet beyond the end of the drip pan were more drips on the floor. Of course, there were smaller tanks for subframes and even smaller ones for small parts.
Factory Chassis Black is not paint. It's a semi-soft asphalt coating in a thicker liquid consistency. I can't remember for sure if they heated it or not but it probably was to set up as fast as it did. It stunk in the area like it does when you roll by a new road asphalt job. New frames, etc, have runs and sags everywhere.
About oil changes.....The assembly plants often built cars with defects that were too expensive to fix. So if they were driveable they distributed them to the factories to use on site only. They NEVER wasted money on oil changes, tires, or anything else. Just keep putting gas into it until it couldn't be used anymore. Then scrap it and write it off.