My engine almost got rebuilt and Its been fine for about a month. Now my car is knocking under the hood and its loud. I checked the oil, but it said it was full. I don't know what it is and I put 800 dollars into getting this car fix and I've only had it for 4 months. Its got 109 miles on it. So I'm wondering can it be repaired or am I gonna have to get a new motor, or junk it?