One big reason not to run water only.. If it gets too cold, something with probably crack.

 

If you open the cap with 100% water in the radiator it immediately goes from being a liquid under pressure to a vapor. So if you open that cap you risk an instantaneous conversion from a liquid to a gas. A gas takes up more space than a liquid so the rapid expansion of the water vapor may come rushing out ion the form of high pressure steam.
That is not good. Just be careful your walking the tight rope!
Hopefully your next step will work!
Good luck!
Mike

 

i have been messing with cars for years now and never realised the importance of antifreeze but after reading about it i shall never take it for granted i have now reflused system adding a 50/50 solution

 

think i have sorted it after doing another flush and addind 50%anti freeze it no longer needs the second fan yahhh hoo

 

Wonderful... Just remember if it starts running hot again (soon) it may only mean that more scale loosened up in the cooling system and is restricting flow again. No cause for alarm... If that happens try the flush we spoke of through the heater hoses at the stat. That way you only loose a little coolant. It's a quick and easy flush. 10 minutes.
I have found that sometimes it takes a few flushes to really clean things out... Just don't start chasing the problem elsewhere because you flushed once... I think that many, many people on this site have that problem!
Glad everything worked out.
Mike