Coolant Flow Direction and Diagram

Hi all, here are some diagrams from my investigations into what direction coolant flows in our block and elsewhere. Hope it helps someone

 

If you asked, I would have shown you this:

Edit: Both of the smaller lines going to the res are likely air bleeds.

 

I was aware of this diagram but
1. It isn't that pretty
2. It doesn't explicitly denote direction
3. Mine makes it easier to visualize IMO

 

1. Easy to follow though
2. Flow is always in through the tstat housing and out of the head water manifold; can really only go one way.

Edit: Point 2 is obvious to me because the water outlet manifold on the head is where the engine coolant temp sensor is...That *should* be the only clue you really need there, considering there's a bypass route directly from that out let to the tstat.

Also directionality should only matter in a system like this where you need to know where the hottest and coolest points in the system are...Otherwise it's pretty much in equilibrium and shouldn't matter.

 

So how is the water pump getting fluid past the thermostat when everything is cold? I'm used to domestic V-8's where the thermostat is on the top of the intake for the radiator return line. This Mazdaspeed 6 I'm working on has the t-stat on pump suction. I have the engine full and a new metal impeller pump, with corksport throttle body, so that is not cooled.

Is it possible to get a new water pump with opposite rotation by mistake for this engine?

I am running this engine on a test stand with a head tank for coolant reservoir. The tank is 5 gallon and is high enough so that both radiator lines are underwater. And not getting flow after the temp gauge shows engine is warm enough.

 

There's a bypass that runs from the outlet to the tstat inlet. See my (fixed) image above in second post.