he is correct. ICE powered industrials do not generate movement heat.
they do generate all normal weapon heat though.
Total War, page 158
Fuel Cell and ICE-Powered IndustrialMechs: ICE-powered IndustrialMechs generate no heat from walking or running, a side effect of their engine and structural designs.
Fission and Fusion powered ones however still generate movement heat. of course those powerplants provide free heat sinks.
bit of an advantage. doesn't quite offset the reduced performance you have dealing with the mass of an ICE engine, or the explosive nature of those engines though. but does make them a bit easier to manage.