I have just been told I have a cracked block on my 94 6.5T engine. I was getting coolant in my oil so the shop pulled the heads thinking the problem was heads or gaskets. Both were in good shape. I have read that 1994 blocks were prone to cracks but i understand new 6.5 engines from GM have that problem solved. I am considering buying new engine from GM. it comes with 3 year /100000 mile warranty. Dealer indicated that new engine has different metal in casting. Has anyone had good luck or information about 6.5 engines offered by GM lately?