I have a 2011 Forrester currently circulating Mobil one and I would life to change to castrol edge for the sales in Denver favor edge. Is there am issue with mixing oil? Or just drain and fill. ...?

i wouldn't worry about switching if you want.

it doesn't matter.  don't read all the obsessive oil information on the internet.  you can switch brands and weights all day long.

follow the owners manual and you're golden.

 

30 year old Subarus and 200,000+ mile Subarus run all day long with whatever is cheap and on sale - brand, weight matter not in oil longevity.   again - follow the owners manual.

Agree with previous advise here. All motor oil is good stuff. No one is making, and selling bad oil. The synthetics have a much longer millage use compared to dino oil is what I see.

Keep it clean before name brands. Check!

Thanks for the advice

... All motor oil is good stuff. No one is making, and selling bad oil ...

 

Sorry, but I have to disagree with that statement, because many companies are still making and selling cheap, Bad quality motor oils, with APi services quality classifications as low as SA (from the early 1930's era) and actual requirements are ~ SN nowadays, see:

 

 

As an Example, Look at this "Made in USA" cheap motor oils, available locally:

 

 

(Photos taken with my cellphone from Quarts of gallon Bottles, Found at local gas stations I don't buy cheapo oils)

 

 

 

Kind Regards.

► Edited to highlight certain words in yellow.

Edited September 16, 201510 yr by Loyale 2.7 Turbo

Well, guess I should have said all NAME brand oils are all good. Cheap stuff that you have never heard of their brand name before, prolly not so good. Just wasn't thinking members on this forum would be 'bottom feeders", who would buy rot gut oil.

 

As with all oil, change the stuff regularily. It is cheap insurance that will keep your car running well for a long time. Failure to do so, will contibute to sludge in your engine.