oh! Again, going to vary on how much heat you are putting into your loop. I have mine blowing in effectively making my rad fans also my intake fans.
If this concerns you, IMO it is much better to put fresh air into the rad to cool w/e you are cooling than to draw warmer air from your PC into your rad. I really don't think the air coming from your rad is warm enough to worry the rest of your components.
--pak