I added oil before taking a trip. I used 20/50 and now I hear a knocking sound. I'm not sure where it is coming from. Sounds like a solid knock not a clicking. The sound is constant from a cold start but you cannot hear it when under normal driving conditions. Should I drain the oil out and replace with 10/30?

 

How much 20w50 oil did you put in? That is way too heavy for your engine unless you are in the Sahara...

If it's knocking though, you may have other problems. How long did it run low on oil and how low was it?

 

I added a half a quart before the trip. I drove about 180 miles but the knocking started shortly after I topped off at the parts store. I had no knock before I added the heavier oil.