For the past 3-4 weeks, I saw and heard my master warning light display for less than half a second. This continued and I had no idea what was causing this alert. It happened when I came to a hard stop and/or making a turn. As luck would have it, I just happened to look at my display panel when the alert sounded and I saw "engine oil level low." Checking my oil level, there was no oil on my dipstick. I added 3 quarts of synthetic. I eventually put in another 1 1/2 quarts. Question, how much harm can I expect on my engine? Currently have 146,000 miles. Engine sounds good with no unusual sounds.
You might have gotten lucky and done no immediate damage. But 3+ out of the 4 quarts in the sump were missing, so there could have been some oil starvation to engine parts. It could not have done this engine any favors, let's put it that way. Bearings don't like running without oil, as one example of potential damage.
Keep a close eye on it. You might have scored the rings/cylinders so that now you have even more excessive oil use than before. Time to shop for a new car, I think. In the mean time, try a "high mileage" oil at your next change.......which should be NOW. The quart that was left in there might have turned to SLUDGE.
I killed (severely wounded, at any rate) my 92 Geo Prizm (Chevy-built Toyota Corolla) by doing the same thing. Took a couple years, but oil leaking into coolant and drop in mileage from 40 to 25. I'd have it checked.
A low oil pressure warning is a mechanical emergency. It's not a warning that you're a little low on volume- it's a desperate warning that you are so low that the pump can't slurp any more in to pressurize the system. An engine without oil pressure under load (acceleration) might only survive a few seconds. Given that it hasn't already blown up? You may have dodged a bullet... I'd probably give it a little time, listening for a tell-tale rod knock, but you might not want to own the car too much longer.
I think the OP made a mistake in the original description. The pressure is what matters, and to the best of my knowledge there are no engine oil level sensors installed. I suspect the stopping and turning sloshed the oil away from the pickup in the oil pan, resulting in low oil pressure.
The way I read the 1st post...3 units plus 1.5 units were added...after 3-4 weeks of warnings. If true, your engine is toast.
That's 4.5 quarts in total, which happens to be the spec'd quantity , with an oil and filter change. Where was the oil level after all that, on the dipstick? Hopefully slightly overfilled? If not, you've been driving on next to zero oil.