4cyl Oil Amount?

These are the last 4 oil changes I've done. Solid line is 5qt off the shelf. Dotted line is how much oil came out of my truck. I always fill with exactly 5.5qt, and OEM filter.
I know that the dipstick is almost useless on the 4cyl and I know that there is some disagreement on oil volume. Owners manual says 6.1qt (with filter) - could that be for a dry engine? Could the heads and balance shafts be holding .5qt+ each time I change the oil?

Interval is 3000-5000mi. 90% highway miles. Truck has just about 40k miles on it (2022).
What does everyone think? Am I underfilling/overfilling?
Thanks in advance!

 

You have 20000 miles of used oil in your garage in marked bottles to compare volumes.

You change the oil every 3-5k despite meeting every criteria for the 10k "normal use."

What I think you're doing is way way over analyzing this. If the dipstick says you're fine, you're fine.

You're doing 5x the preventative maintenance of 99% of Tacomas in human history.

Just go by the dipstick. Get a used oil analysis if you need to feel reassured about it. Buy know that you're fine.

 

I think I did 5 quarts on my last oil change. I check the dipstick fairly often and shes smack dab in the middle of high/low. I don't sweat it. Personally I would rather run my overall oil volume slightly low than risk overfilling.

 

What type of engineer are you? Civil, mechanical, electrical?

 

"Solid line is 5qt off the shelf. Dotted line is how much oil came out of my truck."

Where on the containers is there a dotted line? What I see are solid lines drawn with a sharpe...are those the lines you reference? Also, you're putting in 5.5 quarts, but getting out less than 5 during an oil change? Does that including draining the oil filter and any spilled waste?

 

I think you have OCD !

 

The dotted lines are there - easier to notice them on the 1st and 3rd jugs. But yes, I am putting in 5.5qt and getting out 5ish. I've since decided that I don't care anymore, I am doing an oil change every 5 to 6 weeks right now and (too) meticulous about all other maintenance as it is!

 

Do you do a lot of high mileage driving? You could probably double that time line and still be more meticulous than most.

 

Yessir, about 3200-3600 miles/month, lots of mountain highway driving as well as dusty roads, or else I'd be more comfortable going to a 7500 or 10k OCI

 

Ah, definitely sounds like you've got the justification, then. Cheers!