Hi Clive, i remember looking after this fine little vessel in my earlier years of working for you and your dad. I remember a slight crack or two in the gray engine also. I hope you will still get her up on the plane when she is done. If you need assistance, you know where i am
Some perkins used oil coolers on the engine as well as gearbox coolers. Its possible that an o ring has perished or corrosion has set in from the raw water side. Might be worth checking out. Lee