It’s a simple question with a complicated answer with two schools of thought on the subject.
According to the first school of thought, oil is best changed prior to winter storage so that the dirty oil doesn’t sit in the pan all winter and damage parts of the motor. The second school of thought dismisses this and favors changing the oil in the spring in order to avoid any condensation during the winter months damaging the motor.
One MontrealRacing.com member has suggested that oil cannot take on humidity or break down during winter storage, therefore it would be best to change it in the fall. Many other members share this opinion.
An Outside Opinion
Jean-Simon Ruel, co-owner of a garage called Fujeetech Pro Sub which specializes in Subarus owns a vehicle he uses only in the summer. Ruel changes his oil every 3000 kilometers so it’s always clean but he wouldn’t hesitate to change it before storage if it wasn’t perfectly golden on the dipstick.
However come springtime, he ALWAYS flushes the oil in favor of new fluid even if a change was done prior to storage. He also lets the oil drain slowly over the course of a day which he feels is superior to a quick flush. Humidity in the oil can depend on the location of storage but Ruel says it’s always present after a winter of downtime.
Another Debate
There is also a debate on whether to start the car during storage to get the fluids going. According to Ruel, starting the vehicle creates a lot of condensation in the exhaust line. “It’s the equivalent of a glass of water for a warm up”, he says. It also takes a lot of fuel and can clean the cylinders effectively but also contaminate them if done too often. What Ruel suggests is to connect the battery but disconnect the fuel line and turn the car over for 10 to 15 seconds in order to get the oil circulating. Once or twice per winter should be sufficient.
Finally
It’s difficult to get a census on the internet but Ruel is adamant that flushing the oil in the spring is the best way to go. “And despite the temptation, you really have to avoid pushing the car before the job is done! This way, you ensure a fun summer with no problems” concludes Ruel.
