2004 Saturn ion cold start engine knock

My Saturn just started recently making a knocking noise during a cold start. It only happened about three times last week when the temperatures were probably in the 50’s. It hasn’t done it since. I checked with the guys on ion forums and they said it could be that my anti drain back valve isn’t functioning or the spring that pushes down my filter since it’s a cartridge filter, might be crushed. I check the filter and there doesn’t seem to be any problems with it. Another person said the timing belt tensioner, but if it was that wouldn’t the knock be happening all the time? The knock only happened when the ei started the engine in the morning and would go away after like 2 minutes of warming up. I’m not sure where to go from here, I want to know of any serious damage is being done on the engine internals.