FWIW I still sell early drive E motors, but it's rare. We don't deal with many of them at this point because they are beyond are ability to certify and don't buy older stuff for the lot. So the only ones I get would be traded in. I'm fortunate that we keep high standards for used cars because if there is a risk of it being a burner we'll offload it ourselves to the wholesale chain. If we sell it certified and it turns out to be an oil burner then we've inconvenienced the next owner, but the CPO will cover it if it's bad. Normally it's rare we would drive a car 1000 miles to know it was burning oil, though right now we are putting nearly all our used cars in the loaner fleet due to inventory shortages. So most dealers would have no idea it's an oil burner unless they were the ones that diagnosed it. I've worked at places with lower standards too though. But thankfully everywhere I've work has done a good job standing behind major issues if they had been overlooked, even on as is. So who you buy things from does matter too. But in the OPs case, they purchased the car 4 years ago. It would still be under CPO if it had been from a Volvo dealer as Volvo had the standard 7 year 100k then.
It's a sticky situation.
Assuming the customer has never reported the consumption issue (out of warranty and knows he/she won't get good will assistance)....Then the only way dealer would know if the vehicle has a consumption issue (or worse) is to take vehicle into the service bay and have techs check cylinders for scoring. Of course, that would confirm the car has a consumption issue
and also needs a new engine.
Of course, if there's no scoring, then the only way to find out is drive the car a few thousand miles...Which won't happen.
Creating the proverbial ethical quandary.
A. CarMax / Carvana seems to not care / know about consumption issue. And are paying top dollar.
B. Feign ignorance and pass the buck onto someone for else via Private Sale
C. Most if not all Volvo Dealers know about the problem, and are probably leery of touching Mid 2016s and Older.
Best case scenario is a Mid 2016 has its 7r / 100K CPO term in 2023. Most 2015.5s are going to reach terms by 2022. Mine expires June 2022. This assumes that the vehicle hasn't yet reached 100K. Which I am sure many are very close or have surpassed 100k. I've got 8400 miles left / 8 Months left. Chances are those 8400 miles will be exhausted before June 2022.
People who still have a valid CPO are not likely looking to offload their cars, since the issue would be fixed at no cost.
When buying a used car it's important to look for things. As implied above, every car is for sale for a reason. Many of the reasons have no implications on the car (end of lease, person passed away, person just wanted a new car). But you should try to determine the reason and mitigate risks. I find it curious that people focus so much on the best deal and so much lower time looking at a vehicles history. It's generally a good idea to pay more for a better used car. I think if a car is new enough to get CPO and you don't it's dangerous.
Age plays a factor. Older the car, the greater the likelihood the vehicle being sold has major faults. Even with a newer car, ascertaining WHY it's being sold is important. Never safe to assume little Old Grandma Died, Gave Up Her License, etc. And the vehicle is trouble free.
Complete Maintenance Records are imperative. A new car could an issue if the little old lady skipped service visits, too.
When I bought my car in June 2016, the dealer offered to "lower the price" by $1600 and remove the CPO. Seeing the car had 2200 miles and 2 years of age (Manufactured June 2014. Put into Service June 2015 as Demo / Loaner. Bought June 2016). There was no way in hell I'd buy a "used car" even if ever so slightly, without a warranty.
Good thing I did. Oil Consumption ($5k). Thermostat / ECM ($1k) - Under CPO. Not sure if my mirror Motor Dying was CPO or not. Either way, CPO paid for at least $6k in warranty, if not a bit more.
But the car industry is still horse trading. Dealers and customers can end up with the short end of a stick. If you want to try to do things in the most upright way you could go to carmax and tell them it uses some oil. They might make a big deal and they might not. If they knock it down what you consider to be okay then take the offer and feel good about your choice. They genuinely might not care much. If they are selling for $18k then the trade is probably around $13k. If you paid $18k 4 years ago, that's $1250 a year... which is pretty cheap for vehicle depreciation of 4 years 53k miles. So I wouldn't fret over the current market. Your car is worth more because of it. So trade it in and buy a CPO and get the 5 year extended wrap warranty.
Let's be honest, very few consumers are going to have a "Moral Reckoning" on telling Carvana or CarMax the vehicle burns oil. Especially if this vehicle is their only source of transportation. Even though the market is paying top dollar for cars, replacing a car requires
also paying top dollar.
There's no real winning solution. Other than steer clear of Drive-E Volvos made mid 2016 and earlier
that have not had the piston rings replaced or
are not still under the old 7 yr / 100K CPO.
Too much of a gamble.