Sounds like the wrong application for a Ventrac. It is intentionally built low to the ground for stability on hillside mowing operations. It was never intended for use on rough areas with protruding stumps and rocks. It is a TURF tractor. Turf implies grass growing on smoothed areas be they flat, rolling, or sloped.
If using a side discharge finish mower deck, the expelled clippings are sent far from the tractor so the radiator screen seldom gets covered. However, with a rear discharge deck such as the Tough Cut or Contour Mower, clippings are expelled directly under the tractor. You have to keep an eye on the temperature gauge to determine when the radiator screen needs to be cleaned.
If using a side discharge finish mower deck, the expelled clippings are sent far from the tractor so the radiator screen seldom gets covered. However, with a rear discharge deck such as the Tough Cut or Contour Mower, clippings are expelled directly under the tractor. You have to keep an eye on the temperature gauge to determine when the radiator screen needs to be cleaned.