The 1k inlet hose is the one that's tricky, it mounts from within the cab whilst the outlet from the engine bay. To mount the inlet from the back of the head I would need another bit of hose additional to old kinky runnin 180 degrees to join up, hence why I just ran the outlet to the rear. So The question remains what is the direction of flow for the heater loop? Does it matter which way round the hoses run?