Change oil before or after winter storage... or both?
 

I will have about 2500 miles/6 months of use by the time I keep my car garaged for the winter and will start it once a week to idle for 5 minutes. Then it'll come back out for spring at about 8 months of use. Now my dealer threw in the 3 years/36k miles of free service/maintenance. That plan recommends the first oil change service to be done at 7.5 months/7.5k miles. Should I claim the first service before or after storage or should I change oil both before and after storage?

I used to fret about this when putting the Lotus away for the winter. This spring, when my mileage was indicating it was due for a change, I sent a sample into Blackstone for analysis. The result? I almost got yelled at for changing the oil; I could've gone another few thousand miles based on the additive pack and TBN alone. Water and gas dilution was no concern, even after a winter of sitting a month at a time.

My advice based on the above is to wait for the mileage to be due and don't stress about the time or the winter. The only counterpoint I can think of is to change it before winter just to get rid of the break-in oil.

In the end, perhaps do it on one side of winter, but there's no good reason to do it before and after winter. When you do go to warm up the car, run it longer than 5 minutes; ideally drive it until the car is thoroughly up to temp, but if you're just idling it, give it some revs here and there until it's fully up to temp, then let it run a few minutes longer. The longer you run the car the better, as it'll give the oil the most time to warm up. Once a month is fine; just keep a battery tender on the car.

$0.02,
Ryan