'97 Summit 670 coolant leak into case?

Oil in the coolant...maybe but if there is a leak in the engine (head gasket) possibly since this system is typicall a closed recirc system, but coolant in the oil not likely. The oil circuit is gravety fed and one way through the oil pump. Coolant leak in the engine typically results in coolant level drop and the fuel in the crank case floats on top of the coolant. Not seeing an easy explanation for your water/oil mixing. Check the plugs for water beads. There is a coolant pressure tester. It a pump and guage that attaches to a non venting cap that goes on the coolant bottle. Pump it up and see if the pressure drops over a couple hours. If it doesnt then there is no leak in the system. The one I use is made by snap on and is also good for cars

oil/coolant mix

I ha

oil/coolant mix

I had the same thing happen to my 97. After I tore it down I found the rotary valve/water pump shaft had some rough spots on it causing the seals to leak between the systems(pretty sure there was a oil return at the bottom of the case). I found some summit x cases and rebuilt them using my crank, replacing all seals and any bearings that felt bad or worn. Notched out my R/V cover(guy sold me a non x) and cylinder skirts to match the x cases. Don't use a carbon fiber R/V, it wears the **** out of your cases. Thats why I switched cases.

Zack knows what he's talkin about. Bet dollars to cents its the waterpump shaft.