[Rick Parker]

Brent do as Pat said. What you are attempting do do is reseal a low pressure (7#-15#) leak in the coolant transfer passages between block & head. This is much like a ("Radiator leak") in that when pressure is developed in the cooling system it has compromised one of many transfer hole seals between block & head. Give the product Pat suggests or if Subaru is not nearby; go to Chevrolet or any GM dealer. Part # 12378254 $4.69. It is a package of 2 or 3 large pellets (1' diameter) that are put in the cooling system, they disolve and seal the problem. Very common for the techs to pop them in a cooling system as preventative maintenance if they have had to remove the heads or manifold during a repair. Do this before expending the effort in remiving the head. It works!