Oil change interludes on low-use vehicles
I would like your thoughts on two oil-related questions. The first is: What is the oil change interval for engines that are not run but 500 miles or less per year, and then placed in storage for snowy winters? And the second question is: When is the correct time to change engine oil when cars are going into storage?
I was always told to change the oil and lube the chassis before putting the car into storage in order to remove any acid or other contaminants in the oil. I realize you may get some condensation in the oil from sitting over winter but this would easily evaporate when the engine is run in the spring. But now I have been told it is better to leave the oil in the motor and change it in the spring before starting. I am sure it would be best to change in fall and spring but that seems to be excessive and too costly.
I change the oil in my cars before putting them into storage for the very reason you stated. Carbonic acid forms and gets into the engine oil primarily as a result of cold starting. And if you’ve ever seen the worm tracks that this acid will eat in rod and main bearings over time, you will know why I follow this procedure. And yes, moisture can condense in the crankcase of an old car with an open system and a breather, but unless the car was submersed in water during a flood I don’t think it would amount to much, provided it is kept indoors and on concrete rather than a dirt floor.
What condensation that would be there would evaporate out the first time the engine is warmed thoroughly, which actually takes about 20 minutes. The temperature gauge only tells you head temperature; so don’t be tempted to shut the engine off early.
Another thing that almost nobody remembers to do is to go out and turn the engine over by hand about once a month so the valve springs that were compressed when the engine stopped won’t develop a set in them and lose their resilience.