Norm in Ontario

Hi My running Subarus with the 2.5 engine are much older and give no head gasket problems. I use the little bottle of Subaru antifreeze conditioner with each coolant change. The engines have as much as 400,000 km on them, (about 250,000 miles). I find that as the engines get older they leak at the valve cover gaskets, which is not a big deal. A leak at the back of the engine, located between the motor and transmission is a royal pain. My solution is to park where it doesn't matter if a bit of oil drips. I learned some time back, to only use Subaru transmission fluid. My use of another premium brand, let to my having swap in a transmission out of a parts car for my 1998. I hope this helps Norm