Yes, I replied to your first post when you described the runaway with a link that described why it ranaway. At least a few people mentioned it as well but I will say it again, that thread had a ton of misinformation.
First, your state may have warranties on cars purchased from new and used car dealers. The terms vary by state. $2,500 is actually a pretty good price and they sound like they are doing their best to make you happy. If it comes down to it, have their insurance take care of the engine - that's what it's there for. If it really comes down to it, have your insurance take care of it and have them send the bill to whoever.
Was it a totally new engine or did it have any parts swapped over? They could have swapped over bad parts. In addition, junkyard parts usually have a warranty. If they took care of the labor, the parts warranty goes on the junkyard to get the replacement and they redo the labor. (This assumes the part they got was defective and not something else like install error). If that's the case they take it up with the junkyard.
Diesel in the oil is rare. The fuel injectors are sitting in the cylinder head and exposed to oil. There could be a bad seal at the injector (the fuel rail is built into the cylinder head), a streaming injector, or a cracked head.
Lastly, since you said it ranaway until the engine died, pretty much anything on the old engine is suspect without further inspection. The usual cause is a leaking turbo and they said it was fine which is possible (don't know if they were talking about the old or new one).
It's also possible if they put a new timing belt on the new engine that they screw it up and caused bent the valves.
First, your state may have warranties on cars purchased from new and used car dealers. The terms vary by state. $2,500 is actually a pretty good price and they sound like they are doing their best to make you happy. If it comes down to it, have their insurance take care of the engine - that's what it's there for. If it really comes down to it, have your insurance take care of it and have them send the bill to whoever.
Was it a totally new engine or did it have any parts swapped over? They could have swapped over bad parts. In addition, junkyard parts usually have a warranty. If they took care of the labor, the parts warranty goes on the junkyard to get the replacement and they redo the labor. (This assumes the part they got was defective and not something else like install error). If that's the case they take it up with the junkyard.
Diesel in the oil is rare. The fuel injectors are sitting in the cylinder head and exposed to oil. There could be a bad seal at the injector (the fuel rail is built into the cylinder head), a streaming injector, or a cracked head.
Lastly, since you said it ranaway until the engine died, pretty much anything on the old engine is suspect without further inspection. The usual cause is a leaking turbo and they said it was fine which is possible (don't know if they were talking about the old or new one).
It's also possible if they put a new timing belt on the new engine that they screw it up and caused bent the valves.