my wifes 00 xc 600 runs very poorly and smokes a ton. I went through the carbs and cleaned. I pulled the ves boots off and unbolted the valve and the pto side boot had coolant in it. Can a bad head gasket cause this or is the jug cracked. Also when I pulled the plugs after running it, the pto side hole had smoke comming out of it. thought I would get suggestions before I rip into it.