k1vsk, you started out wrong and now you're going deeper
There are no problems caused by propylene glycol expanding as temperature decreases, since it doesn't do that.
If you are an engineer, or studying to be one, I am sure there are many things that you know. My advice is that you should stick to writing about those. Otherwise, people may follow poor advice.
Sarcasm isn't needed or appreciated. I won't argue the point as I'm sure practically no one else cares, however, I don't plan to argue credentials or debate the reference you attached which you might read again.