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.