I think I know the answer, but just wanted to get verification.

After engine break-in (engine not in car) I changed the oil and filter. With new oil I started the engine 1 more time. I have a leak at the oil temp sensor I'd like to fix before installing in the car (for ease).

Can I drain the oil into a clean container then pour it back in the engine after I replace the taco plate seals?

My guess is no, but just checking.

Not in California.

Why not? … you only ran it for a few minutes, right?

The break-in oil and first filter should have caught any initial crap … and you were going to run the second batch of oil for 2500 miles anyway, right?

Filter it through a disposable paint filter when you drain it, and again when you pour it back in.

I don't see a reason not to as long as you drain it into a clean container and filter like Mark suggested. It sure would be a waste to get rid of it after 1 startup.

Yes.

I had to do it once to install my Welt Tuna can.
Then it leaked and I had to do it again to take it off and return it.

AND I need to do it one more time to put the replacement on.
That is on the list for tonight. Car is in the air and I even cleaned out the 9 quart tupperwear tub (dont tell the wife :-)

I done it multiple times when working on motorcycles when fixing oil leaks and changing seals. . Just be careful to make sure there are no impurities before putting it back in the motor. .

I think Ripper is referring to California Smog/Pollution/Environmental Acts.

Should not be a problem as suggested above along with running it through a filter/strainer. Look at the oil to see if there is any metallic particles etc. in the oil.

I have done it before