Most dozers have reversible fans blades... If you look at the hub of the fan it's probably got a spring/hub arrangement there where you push the blade in and turn it 1/4 turn to reverse the direction of air movement.
That said... yours is set up to push which is normal for summer operation. You can turn them around now but I absolutely GUARNANTEE you... after an hour you'll turn them back. The heat that sucker will dump back on you is unreal... It is great for winter use tho.
What you need to do is just get in there and blow the rad clean. If it's got an oil film on the back side you need to get some gunk and soften that up and hose it off.