Recently bought a 98 6.5. I knew it had engine issues and plan on fixing it, previous owner said it was losing coolant and bringing up the oil levels so he parked it. I got it running and checked things out, the oil was very thick but I drained it off and flushed it, the engine runs and sounds good, good oil pressure, no overheating or white smoke, is there any way I can tell if it is a head gasket issue or a cracked block other than taking it apart? Hope to pull the heads soon. Thanks.