I then turned my attention to the cooling system and another bit of surface rust on the rear valance. Started with mechanical rust removal using my Black and Decker sanding file and a drill with wire brush attachments. Then cleaned it up and used the Bilt Hamber Deox Gel to remove any remaining rust chemically.
I filled the block up with coolant by sticking a hose into the outlet and filling till it reached the top, the refitted the hoses and filled the coolant reservoir until it came out of the bleed screw, managed to get 8 litres in this way, so hopefully only half a litre or so will be needed to top it up.
I pressure tested the system before I filled with coolant and managed to find a few leaks, one of them necessitated a new hose from Porsche (odd shape and tapered - £30). I did this again once the system was full of coolant and found more leaks which were fixed by tightening hose clamps. Eventually I got it to hold 15 PSI over a couple of hours which was good enough for me.
