Overheating, again!

[Fuzz]

coolant was leaking at an alarming rate until i put radwell in.

How about fixing it instead of bodging it up.


Random guessing game....
Bearings have started to go in the water pump, causing the leak and allowing impeller to touch the casing, which in turn prevents any coolant flow happening.

 

[Janesy B]

Radweld has probably plugged the gap and the coolant system. HGF on a Ford Sigma (Zetec-SE) engine is very very unlikely. Fix the coolant system.