I haven't had that problem with my viking yet although I can see where it could happen. My father has a Rhino and he was having a hard time keeping his Radiator clean n it and we used plexi-glass to build inner fenders for the rhino that extended all the way to the front bumper and then painted the plexi-glass black and now you can't even notice its there and we have had NO mud touch the radiator. But to be on the safe side we also took the windshield washer tank and motor off of a 1989 Mazda B2600 and mounted it along with 6 feet of hose under the hood on the rhino so if it does get muddy you can wash it back out, or when our buddies get there's muddy we can wash there's out, works really well. I will try to get a few pics of the whole thing today and post, maybe you can do something like that on your Viking.