When I use Water Wetter, do I have to bleed the cooling system if I put it straight to the radiator?

 

If you are just adding it to the top of your system with a system that is already bled and filled sufficiently, you don't have to. So i don't think you have to worry about it.

If you messed with anything that could have gotten air in the system or you were running a low level, you would have to.

 

no - but if temperatures look higher after, simply bleed