The Tector engine is virtually the same as ■■■■■■■ ISB engine but with a different badge, which is a development of the old ■■■■■■■ BT engine. That engine had core plugs in the block behind the tappet chest cover. It would also leak coolant into the oil from the oil cooler after shutdown. Usually possible to remove the oil filter and then pressurise the header tank.
AFAIK the ISB does not have wet liners.