I've got a Hyster S50FT (S/N F187V22195K) equipped with the Mazda 2.2L LPG engine and Duramatch transmission that is having overheating issues. The lift runs fine most of the day but towards the end of the day it tends to rise in temperature and set off the powertrain protection system and shut the engine down. I have verified with a temp gun the engine temp is rising to the 250° mark that shuts down the engine so I don't believe its a bad temp sensor. The thermostat has been replaced, water pump replaced and verified to be moving water through the system. New head gasket relatively recently replaced. Radiator fins are cleared of debris and fan spins good. Even pulled the cat and checked the exhaust to make sure there were no clogs causing excessive heating there either. Any ideas on what would cause this overheating?