Engine Knock
 

OK, need some advice on this from you experts. I'll try to make this story short as possible. Last Sept bought a '06 T&C. In Dec we decided to buy a brand new van and sell this one. Because of the end of the year, the dealership wanted to make a sale, so they decided to hold onto the vehicle w/out the title (another long story) so they could guarantee a better trade in value. So fast forward to last month and they finally get the title. They do their inspection on the car (finally) and discover this knock. They call me and say they no longer want to buy it because it is too expensive to fix. I knew nothing of the knock beforehand because it starts after the vehicle has warmed up and you cannot hear it inside. So the mechanic shows it to me and sure enough it's a pretty good knock. He then pulls out the dip stick and shows me the oil. It's a nasty black and super thick. The oil barely even dripped off the dip stick it was so thick. After assuring the mechanic I wasn't trying to hide that when I turned it over to them, he said he thinks the previous owner probably ran it low on oil for too long and I need to replace both heads. What do you guys think?

Well a knock would not be from heads so I dont know why he would say that Ticking would be from heads because the lifters are up there.
Drive another van same engine see if u hear the same sound it could be just the normal sounds for that engine The 3.3 and 3.8 does have a ticking sound that is normal in them.