To preface, I am not a mechanic, that said: My first steps here would be to zoom in on the fine print of what "certified pre-owned" meant which you may have done already.
If I hear CPO I would assume manufacturer CPO which means full manufacturer warranty but dealers can be sneaky and "certify" it themselves, so you need to find out who actually did the "certifying" here. Since you said the CPO warranty is held by a third-party, I'm not optimistic buuuut it could be the dealer sold you on an additional third-party warranty on top of whatever coverage there is. So verify the true CPO status of the car, dig up old paperwork when you bought it.
Failing that, I would read the fine print of the third-party warranty and what it covers since of course they rather not pay. 1 qt/1000 miles is generally the accepted threshold for "excessive" by Subaru, Kia, etc. but you'll have to deal with their exact words here most likely. This doesn't apply to your vehicle specifically so don't treat it as a repair manual necessarily, but could help your case since it states 1 qt/1000 miles as the deciding factor.
While that's being figured out, my first step would be to pull the PCV valve and give it a shake since it's a relatively easy procedure for anyone comfortable with basic auto DIY. See if it rattles freely like a stack of coins/washers or sounds more gummed up and require cleaning/replacement. Not guaranteed to be a magic bullet fix but it's an easy, cheap start but I've seen anecdotes of it helping, potentially mine case too. (different engine however)
And also the obvious check for leaks, I thought my burning oil may have returned but turns out past me just didn't tighten the oil drain plug enough. Oops.
If I hear CPO I would assume manufacturer CPO which means full manufacturer warranty but dealers can be sneaky and "certify" it themselves, so you need to find out who actually did the "certifying" here. Since you said the CPO warranty is held by a third-party, I'm not optimistic buuuut it could be the dealer sold you on an additional third-party warranty on top of whatever coverage there is. So verify the true CPO status of the car, dig up old paperwork when you bought it.
Failing that, I would read the fine print of the third-party warranty and what it covers since of course they rather not pay. 1 qt/1000 miles is generally the accepted threshold for "excessive" by Subaru, Kia, etc. but you'll have to deal with their exact words here most likely. This doesn't apply to your vehicle specifically so don't treat it as a repair manual necessarily, but could help your case since it states 1 qt/1000 miles as the deciding factor.
While that's being figured out, my first step would be to pull the PCV valve and give it a shake since it's a relatively easy procedure for anyone comfortable with basic auto DIY. See if it rattles freely like a stack of coins/washers or sounds more gummed up and require cleaning/replacement. Not guaranteed to be a magic bullet fix but it's an easy, cheap start but I've seen anecdotes of it helping, potentially mine case too. (different engine however)
And also the obvious check for leaks, I thought my burning oil may have returned but turns out past me just didn't tighten the oil drain plug enough. Oops.
