Thermostat located in lower radiator hose, not upper

Question

All the diagrams and videos online show the thermostat located where the engine meets the upper radiator hose. This makes sense because coolant flows from the engine to the radiator via the upper radiator hose. When the coolant is cool the thermostat valve is closed and the coolant bypasses the radiator. When the coolant is sufficiently hot, the thermostat valve is open and coolant flows instead through the upper radiator hose through the radiator.

But in Honda Civic mk8s the thermostat housing is clearly at the engine end of the lower radiator hose.

So how would this work? Maybe in a Civic the coolant isn't drawn up from the lower radiator tank when you first turn on? Instead it just uses coolant sitting in the engine block?

Answer 1

The cooling system is a loop, the coolant does not sit at just one point in the system until the engine is running. All the coolant pipes are full as part of the filling process is to remove the air bubbles.

As for the thermostat being on the bottom pipe, I did that on my v8 when I fitted electric fans - it worked very well - they only came on when in stationary traffic.