how much is too much (engine oil overfill)

[4793]

'02 K2500 with the 8.1, 6 1/2 quarts with filter (standard) change. Using a 2 quart measure, the ordinary procedure is "3 full measures, wing the 1/2 quart, and make sure the oil level is toward the upper mark on the dipstick".

This time around, I got into a zone or something, and just as the last of the fourth full measure went down the fill tube I realized "dummy, this thing is gonna be too full". Consulted Dr Search Engine and got inconclusive results- though it seems less risky in a big slow running engine like the 8.1 I decided the safe thing was to drain off that extra quart and a half. Messy, and not fun.

I believe I learned my lesson, and am just curious to see if there's an informed consensus here as to the question asked in the title.

[hatzie]

That's one thing I've never had a hankering to second guess the engineers on. I have several small catastrophes from things I've done cuz I have to learn things the hard way but not that. LOL

I wouldn't run it over the fill line on the stick.
I'd rather run slightly lower than full than slightly more than full.

The main problem with overfilling is aerating the oil. Air bubbles drop the lubricity and raise the oil level getting more air trapped in the oil going from bad to worse.
It's not just the crank weights stirring things up. The airflow from the pistons rising and falling in the cylinders can aerate the oil if it's high enough in the pan.