Is it normal for a radiator to be warm?

[riassegremy1]

It is my first time using a radiator and I notice that the top of my computer where I put my radiator is getting warm(fans from the radiator are exhaust). Is that normal? I monitor my hardware using HWInfo and I do not see anything gets too hot(all within 40-60c).

There is a magnetic dust filter on top of the case, when I removed it, the warm temp decreases so i am thinking maybe it's because of the filter but then again dust filters are helpful.

Parts used:
CM TD500 case (new)
Cooler Master AIO LC240e (new)

 

[2sidedpolygon]

It's fine. The radiator diffuses heat, so it's only natural for it to get hot. Don't worry about it.