Changing the oil this morning in my 2022 LS 500 and mistakenly started it up and ran for 20 to 30 seconds with no oil in it. How much damage could have occurred? How concerned should I be?

 

No load + running with no oil is much better than no oil while loading the engine. Hard to say, you're probably okay but I'm mostly guessing. I once ran a Sienna with no oil for about 15 seconds same thing I was changing oil and my brain stopped working. Van is still going years later.

 

My 2 cents is that I wouldn't worry about it.

 

Small amount of oil was still in the oil pump and pick up that did not drain fully.
Brief run at idle, cool motor from not running for the time you took to drain, ought to be fine.
Did the oil warning light come on? Were the only screeching sounds coming from your mouth?

 

You are good. I routinely run my engines after draining the oil until the oil pressure light comes on. Have driven hundreds of thousands of miles on my cars.

 

I agree with most you should be fine, like Lex2K said if it was under load maybe something different but you should be fine.

 

On that engine.....maybe fine maybe not. No sense worrying now, just run it and hope nothing happened. You had oil film and whatever oil was still in passages/bottom of the pan plus near no load so it's not instant death, hopefully.

 

This probably occurs at oil change joints more often than we would like to know. Full synthetic oil is very slick. Maybe it added 5,000 miles of wear to your engine, maybe not.
Don’t worry, be happy.

 

I agree its should not be of consequence given the short time and no load.

 

Thanks for all the feedback. The responses are appreciated and certainly help reduce the anxiety over my mistake.

Ha, yes oil warning lights with loud alarms, and there were definitely screeching sounds along with choice words coming from my mouth. I think I lost my religion for a brief moment.

 

Check the oil filter for sparkles next oil change, it should answer your question.