If it isn't leaking externally, then it must be internally.
I would compression test all the cylinders. If they come out fine. I would put the cooling system under pressure over night and then slowly pull the drain plug for the oil to see if a possible intake manifold gasket is leaking. Coolant will drop down to the bottom of the oil pan when they separate.
Monday, January 26th, 2009 AT 12:04 PM