If you had a communication between the cooling system and any of the cylinders, you would expect to see loss of coolant and high pressure in the cooling system. Remove the cap, start the engine and if there is leaking, it will usually show as bubbling in the tank. If no bubbling or high pressure, start looking elsewhere, as there are plenty of other available places for leakage.

__________________
Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.