Coolant flow direction on 351 C

[EBSTANG]

HOW I SEE IT, PLEASE TELL ME IF I'M WRONG.

The ONLY three RETURN pathways for coolant to RETURN to the water pump:

1) Internally, through the brass bypass washer/orifice, up until the thermostat (if you have the correct skirted one & of course, you have a water pump with a bypass orifice) is fully opened. When the correct thermostat is fully opened, this passageway is fully closed. Enough on #1, read all about that subject on OTHER THREADS!

2) Externally, through the lower radiator hose, when the thermostat is open.

3) Externally, through the return hose from the heater core. If your temp selector is on "heat" and you do not have any other inline valves manually stopping flow.

All three of these coolant loops RETURN/FLOW TOWARD THE WATER PUMP, connecting to the FRONT of the water pump, on the FRONT (inbound) side of the water pump impeller. They all go to the SAME reservoir, in FRONT of the impeller, to then be PUMPED INTO the 2 ports on the front of the block. These two ports, on the front of the block, match up with the machined channels, on the backside of the water pump. These channels form two passageways, when the water pump is bolted up to the timing cover. The impeller pumps ("pushes") ALL the returning coolant through these two ports/passageways, on the front of the block.




Coolant does not flow (directionally) from the water pump directly towards; 1) the internal bypass, 2) the lower radiator hose or 3) the heater core hose. Coolant is "pulled" through 1), 2) & 3) All OF THE COOLANT is "pushed" into the 2 ports on the front of the block towards the rear of the block and then travels up to the rear of the heads. Coolant then travels through the heads toward the front where it goes through; 1) the bypass, during warm-up 2) through the thermostat to the radiator, if open and/or 3) the block nipple, into the heater hose toward the heater core....soooo

Correct me if I'm wrong but I believe the direction of flow is FROM the nipple on the block (that location is not the intake manifold) TOWARDS THE HEATER CORE. At some point (past the halfway point of the individual coolant loop?) "push" becomes "pull" and the water pump "pulls" the coolant through the heater core and back to the pump. The water pump is always "pushing" and "pulling" coolant, depending on which side of the impeller, but the direction always stays the same. Technically, this flow circuit (the heater core circuit/loop) also serves as a "bypass" (bypass of the radiator) in that it returns warm/hot water DIRECTLY, back to the pump (and then through the engine) without going through (bypassing) the radiator.

 


I think many of us have all kinds of reasons for wanting to know the direction of coolant flow and the pathway it takes, for various reasons. (different topic) It seems that there is much conflicting info and I've yet to find a COMPLETE diagram showing the ENTIRE PATH or text describing the entire path. For now, let's just get the PATHWAY and FLOWDIRECTION settled. AGAIN, if 1), 2) & 3) connect to the SAME "reservoir," on the SAME side of the water pump's impeller, it must be as stated above.

Please AGREE or ADVISE!

 

[barnett468]

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sounds about right except the water does not go into the back of the block . . it fills up the block and comes out all the holes in the block into the heads then exits from the front of the heads so theoretically, the front cylinders run cooler than the rears.

 

[goodnigh]

.

sounds about right except the water does not go into the back of the block . . it fills up the block and comes out all the holes in the block into the heads then exits from the front of the heads so theoretically, the front cylinders run cooler than the rears.

Going to check that out, cooler front cylinders.

Recently bought a Fluke visual IR thermometer and was

looking for something to do with it. Bingo! I can record

a visual as well as IR image of the engine and with some

luck can upload the video here. Thanks for the project.

mike

 

[EBSTANG]

.

sounds about right except the water does not go into the back of the block . . it fills up the block and comes out all the holes in the block into the heads then exits from the front of the heads so theoretically, the front cylinders run cooler than the rears.

Thanks for the response...so let's assume the block is already full of coolant. The coolant FLOW DIRECTION is from the pump toward/through the 2 passages on the front of the block, at the connection to the water pump. The FLOW DIRECTION then goes upward and "comes out all the holes in the block into the heads." Okay, for clarity, what you are saying is the coolant flows upward, out of the block, through multiple/several passages (how many?) through matching passages into the bottom of the heads. This coolant then FLOWS FORWARD (the only way out) in the heads, where it exits the heads into the front of the block. Coolant from both heads flows together at the thermostat housing/"bypass washer" area, at the top, front, right corner of the block. All of the coolant which reaches this area, from the water pump, must first flow into the block, up and through the heads prior to reaching this point. It can then take route 1) bypass, 2) radiator and/or 3) heater core, as a path back towards the water pump, as stated in my initial post of this thread. Correct?

***I'm trying to understand, which I believe I now do, but more importantly, leaving a flow description for the next guy who wants to know. It's still a little difficult to visualize what the the coolant passages in the block and heads look like. (flow direction is now clear!) It is why it's important for the experienced guys, who definitely know the answers, to agree with this thread and confirm. Beginners can then have the confidence that the information is correct. When 5 or 10 reputable guys confirm, I can let these things rest. So please chime in, even if you agree!!!***

Thanks, Eric

 

[barnett468]

.

sounds about right except the water does not go into the back of the block . . it fills up the block and comes out all the holes in the block into the heads then exits from the front of the heads so theoretically, the front cylinders run cooler than the rears.

Thanks for the response...so let's assume the block is already full of coolant. The coolant FLOW DIRECTION is from the pump toward/through the 2 passages on the front of the block, at the connection to the water pump. The FLOW DIRECTION then goes upward and "comes out all the holes in the block into the heads." Okay, for clarity, what you are saying is the coolant flows upward, out of the block, through multiple/several passages (how many?) through matching passages into the bottom of the heads. This coolant then FLOWS FORWARD (the only way out) in the heads, where it exits the heads into the front of the block. Coolant from both heads flows together at the thermostat housing/"bypass washer" area, at the top, front, right corner of the block. All of the coolant which reaches this area, from the water pump, must first flow into the block, up and through the heads prior to reaching this point. It can then take route 1) bypass, 2) radiator and/or 3) heater core, as a path back towards the water pump, as stated in my initial post of this thread. Correct?

***I'm trying to understand, which I believe I now do, but more importantly, leaving a flow description for the next guy who wants to know. It's still a little difficult to visualize what the the coolant passages in the block and heads look like. (flow direction is now clear!) It is why it's important for the experienced guys, who definitely know the answers, to agree with this thread and confirm. Beginners can then have the confidence that the information is correct. When 5 or 10 reputable guys confirm, I can let these things rest. So please chime in, even if you agree!!!***

Thanks, Eric

it flows thru around this many holes.

....................................................it then is controlled by the holes in this gasket.

.....................

 

[EBSTANG]

.

sounds about right except the water does not go into the back of the block . . it fills up the block and comes out all the holes in the block into the heads then exits from the front of the heads so theoretically, the front cylinders run cooler than the rears.

Thanks for the response...so let's assume the block is already full of coolant. The coolant FLOW DIRECTION is from the pump toward/through the 2 passages on the front of the block, at the connection to the water pump. The FLOW DIRECTION then goes upward and "comes out all the holes in the block into the heads." Okay, for clarity, what you are saying is the coolant flows upward, out of the block, through multiple/several passages (how many?) through matching passages into the bottom of the heads. This coolant then FLOWS FORWARD (the only way out) in the heads, where it exits the heads into the front of the block. Coolant from both heads flows together at the thermostat housing/"bypass washer" area, at the top, front, right corner of the block. All of the coolant which reaches this area, from the water pump, must first flow into the block, up and through the heads prior to reaching this point. It can then take route 1) bypass, 2) radiator and/or 3) heater core, as a path back towards the water pump, as stated in my initial post of this thread. Correct?

***I'm trying to understand, which I believe I now do, but more importantly, leaving a flow description for the next guy who wants to know. It's still a little difficult to visualize what the the coolant passages in the block and heads look like. (flow direction is now clear!) It is why it's important for the experienced guys, who definitely know the answers, to agree with this thread and confirm. Beginners can then have the confidence that the information is correct. When 5 or 10 reputable guys confirm, I can let these things rest. So please chime in, even if you agree!!!***

Thanks, Eric

it flows thru around this many holes.

....................................................it then is controlled by the holes in this gasket.

.....................

Thanks Barnett!

I'll post some pics when we tear sown the motor to show how the gasket effects/controls flow through the passages.