You may want to do some research (you might begin here: MOISTURE -- The Second Most Destructive Lubricant Contaminate, and Its Effects on Bearing Life.) While there may be some engineered product I can't think of a single petroleum product that isn't hygroscopic.

 

Water will combine with oil under certain circumstances but allowing a car to sit still over a winter is not one of them. Absorption of water in oil in conditions below 40% absolute (not relative) humidity is insignificant.

The owners who insist on running the engine every week have far greater chance of inducing condensation and contamination.

 

The problem with winter driving used to be road salt but these days it's the usage of hydrated chlorides. They are extremely pervasive and difficult to rinse away. They will dry on a vehicles surfaces only to be 're-mobilized', if you will, and continue to wreak havoc many months after the original dousing. In fact, rinsing tends to force the stuff even further into the vehicle and capillary action takes it places it would never reach by mere splashing. It creates lots of problems for me, trucks and emergency vehicles have tons of wiring and any nicks in the insulation or unsealed connections will allow intrusion. I've replaced individual wires that have obvious chloride contamination 8-10 feet away from the original intrusion. It's been an industry source of contention for at least the past 10-15 years. And what happens to the wiring? The copper turns black and brittle, resistance goes sky-high and connections fail. Now imagine how mere sheet steel will fare against this intruder... We have support vehicles with full frames that the frames have failed from corrosion - always in the wheel areas, where the splashing is greatest. And these are the frames failing, not just the thin little bits of sheet steel.

Personally, I keep one car that will see winter roads. The rest stay in the garage. Once there's no chance of chlorides being used again, for the season, I wait for several heavy rainfalls and the roads to dry before exposing my cars to any residue. If your car is something you only expect to keep around for a few years do what you want. If you plan on keeping one for a long time you might consider adopting this plan.

 

Agreed. My original point was if one was to nit-pick other concerns that carried little consequence why not worry about ... ;-)

 

And there's the problem- the tendency of turning a simple common sense task into rocket surgery. I've been storing vehicles for 40+ years and there's about 10 minutes worth of work each beyond standard scheduled maintenance.

 

all good suggestions save the oil change in the spring. It’s more prudent to get the old oil out of the crankcase and off of the bearings BEFORE long term storage.

old oil is full of dissolved acidic blow by combustion gasses. They are well known bearing eaters if left to sit on the bearings for extended periods of time. An oil and filter change. BEFORE storage eliminates this pitfall.

Z