[L.A. Mouse]

It has lost compression. There are no metal filings in the oil. It runs, there is no smoke but the motors 'noise' has changed..

 

[stave7119]

Welcome to the forum! What is "it". Model and year so we know what we are working on please. We are going to need the whole story....

 

[latebird]

Running out of oil is never good and the top end of the engine suffers the most - if the crankshaft is roller bearing, it probably was not hurt - if the crankshaft main or rod bearing is a plain bearing, I would advise running it til it quits and install a new or rebuilt motor or you could have your engine rebuilt now to head off inevitable failure because it will fail at the worst moment (5 miles into the boonies when you are by yourself and no phone service).