1999 K2500 Suburban 6.5 Diesel, 160k, just replaced tranny, a couple of PMD's (relocated to hole in bumper, o.k. so far) Low coolant light came on, added coolant. a few days later, same thing. I can add a gallon of coolant at a time now (maybe 50 miles since first time low light came on) and in 10 miles, it will be low again. Yes, my oil has risen, I drained it without warming it up, in case it had water in it, and it came out a mollases consistancy. no notice of coolant/water separation. filled it up again, topped coolant, drove no more than 10 miles, and oil level is up 1.5"- 2". I quit driving it. One dealer says they haven't done a head gasket in a long time, and thought maybe it was the coolant leaking into the oil pan through the engine oil cooler in the radiator. Is this possible? Another dealer says they do head gaskets on these all of the time, $1900 to do both sides. Lucky I have a VW 1 ton Double Cab to haul and do what I need. Any great words of wisdom? Thanks