You cannot determine this until you remove the heads. Either way the heads must be removed and the gasket replaced. After removing the head you need to have it inspected by a machine shop.
To tell if the head is cracked, you have to remove it from the car, so you will replace the head gasket, anyway. Take the head to a machine shop and have it magnafluxed to see if it's cracked.
The head will need to be inspected at a machine shop. They can tell you if it is warped or cracked.
A blown gasket can be repaired by replacing the gasket...if you are talking about the head gasket, then you have to remove the cylinder head from the engine block and replace the gasket that is inbetween them. Cracked heads generally have to be replaced because they are made of aluminum which cannot be repaired permanently once it is cracked.
If you suspect the head and/or the block, have them "magnafuxed" by a machine shop. On the other hand, as you're pulling it apart, check the head gasket and if it's shot, there is usually only the one problem.
blown head gasket or cracked block blown head gasket or cracked block
Could be head gasket, head, or cracked block
cracked head or blown head gasket
Blown head gasket or cracked head.
you have a warped/or cracked head,or blown head gasket
Head gasket Cracked head
Sounds like either head gasket, cracked head or cracked block
A cracked block means that the engine itself is cracked. A blown head-gasket means that the gasket between the engine and the head has blown. Either can be caused by overheating the engine. When an engine overheats the head can warp causing the head-gasket to give out. In some engines the heat cracks the block. If the block is cracked, it's over. If the head-gasket is blown you can always machine the head surface and put it all back together.