Thanks, OK4450, sincerely for the detailed explanation.
Thanks too to you Rally, for adding your perspectives on the problem.
Hopefully the new Subie-Toyota Joint Project engine won’t inherit whatever the actual wekness(es) is(are).
Makes sense…almost all…no maybe all of the ones I have done were the EJ25… Now that I think about it…yeah all 2.5L
Blackbird
If it is just a tiny weeping of coolant, Subaru actually sells a ‘coolant system conditioner’ - $10 at my local dealer. Add that to a full radiator and run it. Subaru started selling it when they found they had major problems with head gaskets.
I still can’t say as I buy the vibrating cylinders theory for several reasons.
One is for the tendency to have higher than normal ring, piston, wrist pin, and rod bearing wear and which is apparently not a problem.
Two is that vibrating cylinders do not seem to be a problem with the old Subaru wet sleeve engines in which the cylinders were held tightly in place by the head gasket only and that if shaky cylinders were a problem then the highways would be littered with long haul truckers whose diesel engines work on the same premise.
(Even some of the old Renaults were wet sleeve motors)