Don't replace the motor you can get it out. I had a 3.1 V6 that started running hot so I figured it was leaking coolant so I added more water and I never did see any leaks so it ran ok for a while then it started running hot again and all of the coolant and water went into the motor. Talk about SLUDGE!!!!!!!!!!! That **** was thick. Let it all drain out and then poured diesel in the oil filler until it was pure diesel then took the heads off and cleaned them up and fixed the the problem and put it all back together and 20k+ miles later it still runs great. Has over 100k miles too.
Go to www.auto-rx.com. It is specially for breaking down sludge. They have forums there were you can ask questions or you can visit the Additives forum at www.bobistheoilguy.com. The stuff does work!
sounds like maybe ur main bearings are shot. have them look at them. I know i had the same problem as far as the ticking was concerned but i bet it could be a problem.