> I'm trying some days of Liquid > Wrench soaking, but at -10C it is not moving much. FWIW, some gentle heat (propane torch, or running engine up to temp) might help. Aluminum contracts more in the cold than steel does, so the head will actually grip the plug. IMO PB Blaster or SiliKroil will work much better than Liquid Wrench, too. Randall