Accidental extreme OCI

Given that and the fact that you are ready checking the oil every week you may wish to consider also keeping an eye on the OCI.

These two pictures come to mind, for no particular reason... :rolleyes::whistle::censored:

I built a spreadsheet modeling the long term oil
life average of consistent loss and replacement with no full change. After many, many cycles of topping off, average oil life becomes:

oil life avg=refill interval\(1-(amount remaining\capacity))

Lubrication properties aren't linear with age though so the usefulness of this equation is limited.I

If we knew miles per week, we could approximate the average miles per quart in that engine at oil change time.
So my stepson did not keep track of his oil change interval. The vehicle is a 2009 Ford escape V6.

I had helped him change the oil sometime back and used penzoil platinum full synthetic and installed a fram tough guard oil filter. After I was done I reset the oil life monitor and installed a sticker on the windshield of when the next oil change was due.

My wife got into his car to move it out of the way the other day, and noticed the oil change light was on in the car. She also saw the sticker on the windshield with a mileage the next oil change was due. It said 141,000 miles.

Well where the problem comes in is the current mileage is 160,000.

When I became aware of the situation, I initially thought no way that could be correct. I mean who would run oil that long. Knowing me I put the mileage at 6 to 10 thousand mile interval on the sticker. So that leaves us at 25 to 29 thousand miles on the oil and filter.

Whatever it may be, I pulled the car in the shop and did an oil change. The oil was pretty dang dark, but not as bad as you would think. It didnt appear to be really thick or sludgy.

Then refilled the car with Valvoline Full Synthetic High Mileage and put a wix filter on it, just because I had some laying around. I also checked the air filter it was the worst I had ever seen, excluding tractors. So I changed it also.

After I changed the oil and filters the car seems to be running fine, as it did before the oil change.

I still didnt believe it was 25 to 29 thousand mile oil, but after talking to him when he got home, sure enough it was. He just left the oil life monitor light on, ignored the sticker and just kept on driving.

So most likely the filter reached capacity and either broke through or the bypass activated at some point keeping the engine supplied with oil saving the engine.

One positive is the car has several leaking gaskets and I add about half a quart a week to maintain level so he doesnt burn up the engine because he doesnt check it. Im sure having a slight amount of fresh oil helped to some degree.

I guess in the future, Im gonna have to keep a better eye on his vehicle maintenance or lack of. The kid is autistic and cars just arent his thing, even though between his work and hobbies does an insane amount of driving. So its really kinda my fault I guess. Im uses to my wife proptly telling me when she needs an oil change and assumed he would do the same as he has before.

I really regret not sampling that oil for analysis. I do still have the filter. Not sure how much oil I could get out of there for analysis or if it would be worth it. So if anyone with a filter cutter wants it to see how the filter performed for 25 thousand plus miles I can send it to you.
Now just change the oil more often until the oil stays clean. Use at least a quart of high mileage oil at each change. Service the other fluids in the vehicle, and don't forget the fuel filter! Some Marvel Ultimate would be great for the fuel and the engine oil.
I would do a second oil change and drain the filter after going 10 or 20 miles.
If using an engine cleaner like Lucas Engine treatment, I would change the filter early. More like 100 miles, not 10. With just motor oil, I would say 500 to 1000.
If the amount he drives is pretty consistent, then you can do a little math to come up with a calendar date that he should hit his next OCI. Set a reminder in your phone and that will reduce the need for physically checking the miles at inconvenient times.

BTW, I have a young, driving kid on the spectrum. I get it.
Nothing can be done after the fact, so I wouldn't worry about it. Change the oil, run a short OCI, dump the oil and filter, refill and return to the normal OCI. Put a big sticker on the windshield to remind him when to change the oil.
Use the recommended amount of HPL Engine Cleaning Oil. Many of us have used it and found it is a safe and very effective cleaner.
No sleepless nights. No worries big chunks will clog anything. Works wonders!!
Yes he did but with 25-29K miles on the old oil, one change wont get it clean. There is still old oil in the galleries, on top of the heads and some still in the pan. I've done a few changes where the oil on the dipstick looked almost as dark after an oil change as before.
The last time I did such a rinse (flushed out the new oil after a 30 mile highway run), I measured what came out and it was about 1/2 qt less than what I put in. So we can expect (depending on the car) roughly 1/2 qt of old oil to always remain in the car. There was a video someone linked on here (you, maybe?) where someone did 5 consecutive oil changes with only a 10 minute idle in between and it took like 4-5 oil changes for the oil to start looking newish when it drained out. Given that, I like your advice, since even 1/2 qt of 25k oil mixed with new doesn't sound appealing to me.
With the constant topping off, the filter is more of the issue than the oil.
Do you still have it? If so, cut it open and take a look at it.

Had a co-worker with a chevy truck that used a qt of oil every 1000 miles and he just changed the filter once a year (10,000 miles or so), said he is adding so much new oil, no need to drain what was in there.
Truck had over 170,000 miles on it, with 70,000 miles of that never having had the drain plug removed.

Heck, my truck uses a qt every 1200 or so, and I am debating when to change the oil and filter, I am at 26 months/4,900 miles on the current fill.
Have debated using a Fram Ultra and my stash of Pennzoil Platinum HM 0w-20 (I have 15 qts), and not changing it till I run out of the oil in my stash. At my current driving rate, that would be about 5 years/10,000 miles.
A college friend drove his new Chevy Cavalier 65,000 mi before the engine finally seized. This was in 1990, and the oils are a lot better now. He claimed he didn't know that he had to change the oil (!) He didn't change the tires either.
A college friend drove his new Chevy Cavalier 65,000 mi before the engine finally seized. This was in 1990, and the oils are a lot better now. He claimed he didn't know that he had to change the oil (!) He didn't change the tires either.
Lol reminds me a of the volvo s40 t5 I bought from my cousin.. Thing had nothing, zero on the dip stick.. Put a few quarts of stuff left around the shop.. went around the neighborhood a few times and it came out in chunks when drained! We estimate it had gone 30k with no added oil. did a oci of around 1k with basic rk oil and filter.. By the second quick oil (2k mi) change it was crazy how much better it was.
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Question is whether it's losing oil or burning oil.

My theory is this (I have no evidence to support this theory, but it seems logical):

If it's only losing oil, at a half quart a week, it's getting the equivalent of regular changes. But you should still change it once in a while just to be safe.

But if it's burning oil, most of the solids will be staying behind. So in spite of all the oil being added it should still have regular changes. Or at least regular filter changes to get rid of the bigger solids, and then a full change once in a while to get rid of the small stuff that doesn't get filtered out.

If it isn't dripping oil you have to assume it's burning oil. And to explain a loss of half a quart a week, it would have to be dripping a lot.
OP said "One positive is the car has several leaking gaskets" so the engine is leaking oil, mostly. Maybe burning a bit but that was not mentioned.