Ok, So i connected the garden hose to one end of the radiator and put it on full....clear water just came out
then i shook it with de-ionised and it was still clear water coming out
THEN i got some distilled malt vinegar, left that in there for a few hours, let it out and it was BLUE?? (previous user must have used blue coolant)
then to get all the vinegar out i did the hosepipe thing for a few mins
THEN i put distilled water through it to clean out all the tap water
so now i am sure it is clean
- can still see some green stuff inside, but it just wont come off, its not doing any harm.