In The Weeds Question
 

I’m not a mechanic so please pardon my ignorance.
Question: If my mechanic puts 5.7 quarts (or full exact required amount of new oil) in my 2021 350 ES, dipstick will show full to top dot. Now, if that is correct, then when the car is started and driven home and then engine then shut off, won’t some of that oil have filled the oil filter and remain there? If so, the dipstick will not include the amount in the filter and will therefore register slightly less than full to top dot?
If so, could it be that this slight deficit is what I have mistaken for oil consumption in my car?

It could be. The standard I follow for checking oil is to wait 5 minutes until after engine shut down.

As long as you're consistent in how you check it time to time, you'll be fairly accurate.

This ensures you have generally the same conditions, let oil settle/drain back into pan etc. the goal is to mimic conditions you checked last time.

Yes, waiting 5-10 minutes, etc, But my point is that even if you wait until the next morning to check it, the amount that now fills the oil filter will make the dipstick reading amount just a bit less than the dipstick reading immediately after the new oil was poured in but engine had not been started and new oil filter therefore empty.
We’re talking about a few ounces here, I guess, but the shortfall in the dip stick reading is very small, too. This could be why, methinks.

There is a FILL SPEC with or without filter replacement.

The dipstick isn’t a precision tool - it gives a close enough/good reading to help you monitor the oil level. The differences we’re talking about are not that serious to worry over.

Yes, if you took a reading after oil was added, but before the engine was started, then it would theoretically be higher than after you start the engine (thus filling the filter), then letting the engine cool (letting all the oil drain to the pan) and checking it again.

The other factor to throw in would be if the mechanic filled the filter with oil first. I always do that. In that case, it wouldn't affect the level much.

Either way, it's kind of splitting hairs. Best advice from E46CT - check going forward at the same circumstance, typically a few minutes after the engine is off.

This is the procedure:

Drain the oil;
Remove the old oil filter;
Put the new filter;
Put the drain plug;
Fill the engine with 5.5 qt of new oil;
Turn on the engine and let it and warm up (if it's cold);
Turn off the engine and let it sit for 10 minutes;
Check the oil level, add if needed to reach the top mark;


Repeat after 5000 miles.



Checking the oil before the first start up (when the filter/channels) are empty is a mistake because around 0.3-0.4 qt will go and stay there.




Now, let me explain why I said 5.5 qt and not 5.7 qt: For example, for the A25A engine Lexus recommended 4,8 qt of oil, but if you did that the engine will be overfilled so after they said 4.5 qt is enough, and they were right. Sometimes their numbers are not accurate, they even say it's a" reference" and you should go with the dipstick.

Now I’m learning the science of this thing. Thank you.
Two follow up questions:
1) How much oil is contained in the oil filter when the filter is full?
2) When the engine is shut down and more than ten minutes elapses, does the oil filter empty of all its oil content?

“Checking the oil before the first start up (when the filter/channels) are empty is a mistake because around 0.3-0.4 qt will go and stay there.”

My dipstick reading appears to be down that much at home right after oil change. I believe the above solves the mystery and is the reason why. After changing and refilling oil but before first start mechanic checks dipstick reading. Shows full and sends me home. After engine started and filter filled with new oil, dips stick reading is just a tad less. The above is why—-not a matter of alarming consumption. Thank you.

1. In the oil filter/housing/upper channels - maybe 300-400 ml.
2. No, the oil filter stays full all the time.

Okay then, now I’m getting it.
Then when oil is first changed and mechanic shows me it’s up to full mark on dipstick, the new oil filter is empty. The car is started and 3/10 to 4/10 of a quart then fill the filter. You get home and shut down the engine. Oil flows back into reservoir where the oil collects but filter stays full. At that point, the reservoir of oil is less by .3 or .4 of a quart ( the amount of oil still in the filter) than when oil was first changed and none was yet in the new filter.
That’s almost a half quart down and very possibly why my dipstick reading at home shows just a bit 1/8” to 1/4” down from the full mark I was shown at the mechanic’s place. No consumption or leak—just 1/3 to 1/2 quart of oil still in oil filter.
Thank you. Riddle solved for this very amateur auto owner.

Hold on there Buckaroo! You dipstick has a low and high mark. The low is when the engine is cold and the high is when the engine is warm to hot. It doesn't care about the oil filter. It only measures what is in the oil pan. Some people say you should only change or check your oil when you engine is warm.
Think about this. If your car sits overnight than your checking the cold reading. Overnight all the oil that's going to drain into the oil pan has.
If you drive around for over 10 minutes your oil is hot and there is a decent amount still up in the engine. You can get a false reading. Also this is when the oil change shop is doing the oil change. It's not their car but they have little choice. It's not the best but OK.
If changing it yourself the manual says to run the engine until warm. Then wait. When do you know what warm is. The gage in your car is not in degrees. The idea here is that warm oil will drain faster. Makes sense but 0-20W oil is very thin right out of the bottle. So it doesn't matter as much as say 10W-30W.
If you want a consistent measurement to go from, check it when it's cold. The oil level should never be below the bottom level. It should also never be above the top level. If it's in the middle, your all set but not at or over the top mark.
Your correct in the amount of oil need for a change with filter. Unless you have a good local mechanic, don't trust the quick oil change places or even your dealership. I've never seen them actually measure how much they are putting in. After filling they check the dipstick. Do you think all of the oil has settled to the bottom of the oil pan that quickly?
Sorry so lengthy. Just thought people would like to know why and how.

I never heard of this - a warm and cold reading for oil? Never makes a material difference when I've checked mine over the years. Coolant yes - has a hot and cold mark on the reservoir.

Thank you for that well crafted response. It touches upon all the “what about” items floating around in my mind while trying to understand why my dipstick reading is 1/4 inch down from full, which is maybe 1/4 quart below full line soon after my oil change. It remains there so I am now assured my car is not consuming any amounts of oil sufficient to cause concern.
BOTTOM LINE: As has been said, dipstick reading is not precise and exact. It’s a measurement of adequacy. So long as reading is anywhere over half between Full and Add, all is well. Check it every few weeks and no need to be OCD about it.
All is well. Thank you!

The best way to check if your burning oil is to always check it cold. Over 6 months you may see it drop a little but that's normal.