Rattle coming from the lower part of engine sounds like no oil but there is oil. What else?

Had a service tech hoist up my odyssey to see what the rattle was - the sound is what you hear when oil is not in engine- knocking / rattling.  He wanted to take of a cover but it would be a huge project to do so.  I have an appointment at the dealer in an hour where I want to pay $70 for a solid answer on what repair is needed, then take it back to the cheap repair shop, but the issue is that if they need to take the cover off the bottom to do the analysis, I'm going to be charged more than $70 and end up doing the repair there at the dealership. I hope to hear from others with the same problem and how it was fixed