I may be wrong but running regenerations the way you did - rpms over 3000 - is not gentle on the engine, at all. it brings coolant temeratures up to their design limit and as the result the coolant expansion thank goes through many extreme temperature cycles. plastic deformation creates weak points on the tank itself with many brittle spots and passages for the fluid to go through. when the system works at high pressure you have leakages until you replace the tank waiting for the next tank to be replaced again and again
