I've got a 98 Komatsu with a Impco Model J regulator vaporizer converter. Purchased the lift recently with the conversion to LPG.

So the regulator freezes up fairly quickly (within 5 minutes). The hoses don't feel warm, so I pulled both the inlet and outlet radiator lines off the regulator and when the lift is running, I'm seeing no radiator fluid being pumped into the regulator.

I do know that a radiator leak additive was added to the system. I certainly top off the radiator with fluid.

I'm not sure what I need to do next in order to check for a blockage in the system & get coolant running to the regulator?