I read about getting the engine hot enough to boil off water and contaminants in the oil. I used to take that at face value in spite of things I knew that were different from that. First, if you keep ice in your freezer, you might notice that the ice cubes shrink. That is sublimation, where the ice cube is evaporating without changing state to a liquid. If you put a glass of water on the counter and check on it day to day, you'll notice the height of the water is going down. It's evaporating. I am also aware that when it comes to humidity, the hotter the air, the more water it can hold.
From those observations, I determined that you don't need 212-degrees (100c) at sea level for water in any state to evaporate. It happens in the frigid environs of you freezer, on your counter top, and in your oil pan. The water won't emulsify in the oil pan. It will separate out. In the immediate, if there is some abnormally high amount of water, it will sink to the bottom of the oil pan, but through evaporation, it will migrate through the oil, into the space above and out to atmosphere. I've read where the combustion byproducts can mix with water and form acids that can eat engine bearings. I've never read how that happens. And it's not because I haven't looked. Maybe it is out there somewhere. I know water can't mix with gas, oil, or other petroleum products, so I don't know what that water is mixing with that forms an acid. And water can't turn into something else unless it's subjected to a lot of heat and pressure. And the water won't displace oil that might be in place with a hydrodynamic bearing. I don't know, but it just doesn't seem necessary to get the engine fully up to temperature and operating that way long enough for something to occur.
I have a car that I don't drive but maybe once every couple of weeks for five or 10 miles or so. It's a 2008 Saturn Sky Red Line. I've owned it since new. I had a Blackstone oil analysis done last year out of curiosity. It showed a tiny trace of fuel. Absolutely nothing to be concerned over. No water. No antifreeze. No insoluables, like soot. I can post that report up if you'd like just so you can see for yourself. My point being that this is a car that by Internet knowledge should be all blowed up because I'm not doing anything the Internet says I should be doing. I don't run it long enough, or hard enough to purge all that nastiness out of the crankcase.
I would add that the real downside to just running the engine in the garage when it could be out on the road is that it won't put a smile on your face. Okay, you want to avoid salt. And yes, with cold roads, you can't lean into the throttle since the tires just spin. And if you are like me, the heater isn't plumbed in so you don't get any comfort. There is one real downside and that is for flat tappet cams, you might not have enough engine speed to properly lubricate the cam. So make sure you vary the RPM enough to keep the cam lubed.
