[Jagdpanzer]

If it is a blown head gasket or injector housing gasket coolant leak do not attampt to crank the engine over before removing all of the spark plugs or you run the risk of greater damage if a cylinder is full of coolant. With the spark plugs removed crank it over to make sure the cylinders are clear. Then install the plugs and start it up with the cooling system pressure cap removed. If the head gasket is blown bad enough to cause to the running problems you have discribed you should see air bubbeling out of the coolant pressure tank.