Engine tank heater install ???

[BobT]

This may seem like a really simple question.

My tractor has one of those tank heaters installed on the cab heater hose circuits. Yeah, it has a heater for the cab although it isn't very effective. Anyway, one thing that caught my eye is the way it was installed. It's plumbed so the heated fluid goes in on the top of the engine right behind the thermostat and the return is drawn from low on the engine block. This seems backwards to me since warmer fluid will rise naturally. Also, it would seem that it would be more efficient to put the warmed fluid in near the bottom and draw fluid out the top so the entire block is warmed and not just the top end.

Is there a right or wrong way to install these types of heaters?

Also, is it important that the heater is installed upright or can it be installed upside-down or laying sideways?

Thanks.