The acid in the oil etching the bearings while in storage theory is why I change my oil before storage now.
Plus it seems like every small engine manual says to do it before storage.
I've heard this before a lot too. I don't have any data to back up my claims but I've pulled apart several engines that were sitting for years in old oil and I have never been able to find any sort of wear, damage or corrosion from sitting in used oil.
I read a storage post from an oil expert and they suggested to chance oil when putting car in storage and not to start the car at all until removing from storage.They said just starting the car when doing the oil change alone would put acid in the oil and defeat the purpose.
So according to your expert, what's the difference between storing an engine with used oil vs an engine with new oil in the pan but used oil still on all the bearing surfaces as it would be after an oil change if you didn't start the engine to cycle it through?
