[HoosierDaddy]

No coolant in the oil sample is good. If it is losing significant coolant it is losing it from inside the engine or outside the engine. That is probably what CAT will check first. If the engine has been overheated prior to your purchase the head gasket could be compromised. That would allow coolant to leak into the crankcase( which should show up on the oil analysis if it is severe enough), outside the engine (which is not fatal but may not be visible if the leak is slow) or into a cylinder( which could be fatal if it fills a cylinder with coolant after shut-down).