Before I'd pull the radiator I would do two things if your have access to the tools , first thing would be to use an exhaust gas detector , very inexpensive from say Napa , you take off the radiator cap and place the clear tube with a rubber funnel shaped end which sticks into the radiator opening , you put in the blue fluid and run the engine if the color changes to yellow you have a blown gasket or crack in head or block , second would be a radiator pressure tester and atttach to the rad. and pump it to the specs. on the cap , which I would presume is O.E.M. or at least the same pressure rating , start the engine and note if pressure is building in the Rad. , the pressure cap rating is important as water boils at 212 degree , but for every pound of pressure you put the water under it increases the boil point by 2 degrees , so if you have say a 10 lb cap the water won't boil till 212 plus 20 which is 232 degrees , also the rad.pressure tester will test the cap to see if it will hold the rated spec. , you may have to take out the covers that is behind/top of the motor and pressure wash the fins externally as it is probally blocked up with dirt and restricting air flow , you can see the flow of water once the thermostat opens by looking down the open rad. cap , another thing oI have seen is operator will hit the travel lever with his leg and engage the aux hydraulics causing the machine to get hot , just a few ideas good luck