I have a '98 24 valve, in a 3500 drw. what blocks crack, where do they crack, can crack be seen easily? Thanks

 

The "53" block is the block that is prone to cracking. If you look below the injection pump near the oil pan you will see a prominantly displayed 53 cast in the block. If it's not there, you are lucky . The cracks lead to leaking of coolant thru the block to the outside (mostly). Welcome to the forum