Engine donor dodging, mile munching HDI

[Ruan]

I'd replace the thermostat, it makes no difference whether you're towing or not - injected quantity is the same over time. Had HDis on dyno doing testing and monitoring fuel and coolant temperature - with a working thermostat they won't get hot like that and you've got half the airflow on the dyno vs on road. The cooling system in them is designed to keep a stock HDi cool in Dubai all day long whilst holding the engine at full load with lots of reserve capacity. It'd have been pulling off IQ due to the fuel temperature based torque limitation map anyway.