Hot exhausting air from Gen being sucked in by cool inlet

the part you (and I) don't know is what is an acceptable temperature range for the cooling air. It might just be that the specs allow for 160 degree air before the engine is affected.

Think about the temps in a liquid cooled engine. Most are running a 195 degree thermostat which means the coolant in the engine is 195 degrees which is hotter than the generator cooling air.