The owner's manual says "When refueling the vehicle Observe the following"

Not if you need to wait for the oil to drain into the crankcase for a proper measurement.

 

I don't. I've been shamelessly making improper measurements all my life. With thicker oil in the olden days.

These days, the stuff that I'm waiting to drain is 0W-20, and it's already hot. And it's been draining the whole time I've been fiddling with my credit card, the filler door, and the gas pump.

 

I'd rather check oil in the calm sanctity of my garage; it's kinda like church.

Frankly, if I'm waiting to fill up, and the guy in front of me starts a twenty point check, I'm going to get a little heated. In a low-key, suppressed way.

 

Not waiting lead to me over filling last oil change.

What happens when you pull into a busy station with unattended cars at pumps?

 

I do remember the FIRST time I gassed up. Pulled up to the pump, then realized the filler cap was on the wrong side. Did some kind of 3-point maneuver, pulled back into another pump, still on the wrong side...

Luckily it wasn't crowded...

 

When I do that I just reach the hose across the car and fill up anyway.

I had a few opportunities when first driving the Gen 3 instead of my old Gen 1, where the filler was on the other side.

If looking at the dipstick is considered a 20-point check, what would looking at two things be called?

 

That works at all the Costcos and big grocery store stations I've used. But numerous more traditional stations seem to have too-short hoses for this.

 

our 2 PHEV's very seldom have the ice turn on throughout the year. By the end of the year the oil color still looks new.
Unless a car owner is periodically finding oil spots on the garage floor, or the driveway, Etc? That oil is going to be as well captured and is in pristine quality as it was during the prioer gas fill up - or the one prior to that - or the one prior to that. If there's a need to be auto preparedness-hypervigilant, then tire pressure would be a better place to over focus. With most cars that can be done right from the display.
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If someone needs to wait more than one minute for oil to drain back to the oil pan to allow a fairly accurate dipstick reading, then the car has a significant problem with oil retention in the head/valve cover area. Like blocked drain passages. There's no engine made that should hold such a significant amount that it takes minutes/hours to drain to the pan. When you remove the oil pan drain plug, how long does it take to drain 4 quarts? Heads have multiple drain holes.

 

The Outback owner's manual says 5 minute wait.
The channels are probably designed to keep the oil from draining completely with use of the auto stop start, if it isn't simply the nature of a horizontal engine, or simply a period chosen to ensure accurate level measurement.

 

Jack the car up making sure the oil drain plug is the lowest point.
Drain, wait and get all the oil cans opened, replace oil filter and by that time the used oil should be drained, get a glass of water from the kitchen, torque the drain plug closed using a new crush washer.
Fill with half a quart less than needed. Drink the water. Check the dipstick. Check under the car for leaks.
Start the car and off the jacks/lift to a flat surface.
Wait a few minutes putting all but the last can of oil away.
Come back and check the oil level making sure it is not above the high mark (any fill over that is very not good according to the owner's manual) and add oil from the last can waiting a bit between small fills.
Pour the remaining oil from the last can into a resealable glass jar and mark the date on it.
Now dispose of the used oil responsibly.

 

I let the car be hypervigilant about that for me. At first, when I set the TPMS to my desired pressures, I didn't like how far it would let the pressures go below that before lighting the warning light. So then I aired up the tires to the max sidewall pressure, set the TPMS for that, and then let the tires back down to the pressures I like.

That way, the TPMS warning comes on just a couple psi below my chosen pressures, and I add air then.

The downside is the light comes on a lot, including pretty much any cold snap in the weather. But I also did an on-board compressor mod, so it's never much hassle to add air when the light comes on.

 

We leave our 2 cars' tire pressure displays up as a default screens - so we don't need to be reminded if it's low ..... until it drops below the default pressure warning beep.


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You understand that a head is not a bath tub of oil? There is no "reservoir" of oil like a miniature oil pan. Although there may be some small 'cups' on wear items that hold several drops just to make sure there's no dry start. It goes where directed, splashes around, maintains a coating on everything and then drips to the bottom of the head where it disappears down a drain hole. Kind of like how a bathroom shower works when a person is using it. And things can also clog up with sludge, just like a shower drain with a hairball, usually only if using dino oil and not being on top of the OCI.

 

The passages can be designed that when the pressure from the pump stops the time the oil takes to all flow to the sump is extended. Even if not the case, a minute for all the oil to reach the sump sounds too short. Despite cries about 0w being like water, heated motor oil is still viscous, and there is a lot of surface area to those passages and parts for it to cling too. Subaru's instruction is likely to ensure all the 'free' oil is in the sump for measuring.

 

I have a pretty good understanding of engine construction. I've assembled more engines in apartment living rooms and kitchens than most people ever see in their garage over a lifetime. There is never a 100% return of the oil to the sump.

Believe what you wish, but the reality is.....

Feel free to google search for typical engine oil and oil pump flow rates. Keep in mind you have just under 1 gallon of oil in your engine. Whatever volume the oil pump pumps into the engine, it has to be able to return to the sump at the same rate, otherwise you eventually end up with an empty oil pan.

Once the engine is turned off, the vast majority of the oil very rapidly returns to the pan, with a very minimal amount left coating engine components (which will slowly flow to the pan) and some very minor 'pools' that stay in place.