Engine knocking on 1999 Ford Expedition

i juss got a 99 expedition 4 free wit 280000 i was driving it and started knocking wen i look it had no oil much is it to fix it or how much is it to put a new engine... and is it too hard to do it myself to???

Asked by for the 1999 Ford Expedition
Hello, did you need to replace your engine to fix the knocking noise, or was it repairable?