Cracked head

this is not a really common problem personally this is the only one i have seen with a cracked head on it, it does happen. most of the time have seen valves and most likely valve seats go bad all the time i have one i just did an engine on, one i have a head to do on and two more sitting in the yard for the same issue or issue as a result of bad valve seat all around 700K on the miles. that being said anything is possible i have even seen a crack between the hold down for the injector and injector housing. pissing fuel into the oil it just one of those things that happen i guess i dont know how the valves looked, it doesn't seem like they were bad at all. i would suggest you just returned it and never told volvo for the crack they would have never figured out the core charge and you would have saved some money. the price is not bad. i just priced the head on a 13 today it was about 3900 my cost with no core charge core charge is another 1200. so as long as you got it done its better now. usually it extends the life of the engine a lot more i have only seen d13 go bad mainly 90% is because of valve problems.