[De Clarke]

I don't know what else to call it. When I use the wipers, or wipe the windows with a clean cloth after a quick rinse, I see temporary "ghostly" little ovals and circles on the outer surface. They seem to disappear as the glass dries completely.

Does anyone know what those are?

 

[The Other Tom]

Hard to say without actually seeing it, but maybe your windshield has a coating of some type....maybe wax or rainx? I know when I wax sometimes the wax "dust" gets on the windshield when I buff it out.

 

[JC Bolt]

My guess would be that the glass windshield, which is essentially silicon dioxide, has a strong affinity for the polar water molecules through attractive forces such as hydrogen bonding (you may have heard the term in a college chemistry class). While the wiper will remove the bulk of the water through mechanical action, a very thin film residue is held in place by the aforementioned hydrogen bonding. With time this thin film does evaporate (liquid phase to gas phase) and the "ghosts" disappear!

 

[The Other Tom]

My guess would be that the glass windshield, which is essentially silicon dioxide, has a strong affinity for the polar water molecules through attractive forces such as hydrogen bonding (you may have heard the term in a college chemistry class). While the wiper will remove the bulk of the water through mechanical action, a very thin film residue is held in place by the aforementioned hydrogen bonding. With time this thin film does evaporate (liquid phase to gas phase) and the "ghosts" disappear!

Interesting theory, but wouldn't all windshields do that?

 

[JC Bolt]

Interesting theory, but wouldn't all windshields do that?

Everything else being equal, yes all windshields would do that. While I like the explanation for the phenomenon (so far) there are many other variables that are involved for which we don't have data. A major one that comes to mind is temperature, especially comparing an EV to an ICE car. Could it be that because an ICE generates a lot of heat it is more likely that there is some windshield heating whereas a Bolt may be cooler, thus allowing for the weak hydrogen bonding forces to manifest. A warmer windshield would interrupt this weak attractive force. We also don't know anything about the history of the glass (by owner or out of the factory) or about composition of the wiper blades or their force on the windshield.

 

[Stovebolt6]

How old is the car? When I did my first wash of my '19, I found what looks like marks left behind by the protective film that GM wraps the cars with for shipping. My theory is the car was shipped in sub-freezing weather to the dealer and the dealer tore off the plastic film while it was cold. Maybe some of the adhesive (if there was an adhesive) or a microscopic layer of the film itself was left behind. My rear hatch had what looked like zebra stripes whenever it fogged up. I tried every glass cleaning technique I could find and eventually the stripes faded, but they aren't completely gone. I'll bet the same thing is covering the painted parts of the car, only I can't see it. When it warms up a bit more I will be doing a complete clay bar and polish prior to the first waxing of the season.