Originally Posted by WobblyElvis
I live close to you and suffer a similar climate. You didn't state the type of driving you do or how many kilometers a year but I will assume it's similar to my own. I put 200,000 km on a car while changing the oil/filter twice a year [ spring and fall ] or approximately every 13,500 km. and I learned a few things by looking under the valve cover and sending in a few oil samples.
The engine got a little dirty as small amounts of sludge started to form in the corners, The engine stayed much cleaner on cheap conventional oil using 8,000 km OCIs as the previous owner had done. Used oil analysis showed increased wear, fuel dilution and insoluble levels during the winter months as opposed to summer months.
Over all the engine outlasted the rest of the car and was still in good condition at 374,000 km when it was scrapped. I learned that if I was going to change oil only twice a year I would make the OCI longer in the summer months and shorter in the winter. Maybe change April 1st and Nov 1st. a 7 - 5 months split.
Everyone's driving habits and conditions are different, and engines are expensive, so you want to be cautious. A UOA does not tell the whole story but it helps. I wouldn't really recommend you change oil only twice a year unless you keep a close eye on the engine.
You're right, I realized after I posted I didn't mention the driving. It's typically 80% highway 20% city. I realize I wasn't being totally clear.
My aim is to change the oil either twice a year or at XX,XXX kms. Typically with this car I won't make it to 6 months. I change the oil when I do the winter tire swap and hope to not hit the mileage until it warms up and I have use of the hoist (when my summer toy comes out).
To be completely honest, I'm thinking my target OCI for this particular car is going to be 10-12k or 6 months whichever comes first with the oil changes being Oct/Nov and April/May (if I make the time limit.) Other than that I'll have to take the car off the hoist to change the oil on the pontiac.
My wifes 2013 Santa fe is the one I really worry about. She drives less than 10Kms one way to work so it never really warms right up. I have her Park it in the heated garage in an effort to speed up warm up time in the morning at least and we drive it for evening running around and weekend excursions. That one does way less mileage and usually hits the time limit.
Thanks for the input. Definately food for thought.