I appreciate your advice, but I don't agree.

This car has been in all kinds of weather and kinds of temperatures.
From Montreal City, Quebec to Mata Moros in Mexico.
It was not particularly cold, nor was there any huge temp fluctuations.
Therefore I don't see why the motor housing would just mysteriously crack.
I think I will examine the cabin air intake and replace the air filter while I'm there. Maybe I will see some gaps or lifted seals.