The 3.8L V-6 is by no means as durable as the 4.0L it replaced. Check the water pump for signs of leaking around the gasket and weep hole behind the pulley. Jeep used engine coolant with an orange-red hue. A coolant leak will look like dried strawberry syrup. If the water pump leaked and the coolant got low, the engine could have overheated and caused head gasket sealing problems between the iron block and aluminum heads. Investigate for signs of water in the engine oil, coolant, or oil residue between the block and heads.