Water pump - electric

[Lotsof 3146 R]

Looking at the parts manual to shows the thermostat housing connecting via the pipes to the bottom of the radiator.
I thought the flow was from the engine via the thermostat to the radiator. Am I reading the parts manual wrong or misunderstanding something.
Many thanks for any clarity on the correct flow direction.
PS - I’m really happy with the EWP. And control unit. Even if re-building the engine I’d not want to go back to a mechanical pump.

[rascott]

i am also interested- i read it the same way.
mine is an s-2- just assumed the tc plumbed the same?

[EuropaTC]

Looking at the parts manual to shows the thermostat housing connecting via the pipes to the bottom of the radiator.
I thought the flow was from the engine via the thermostat to the radiator. Am I reading the parts manual wrong or misunderstanding something.
Many thanks for any clarity on the correct flow direction.
PS - I’m really happy with the EWP. And control unit. Even if re-building the engine I’d not want to go back to a mechanical pump.

From what I can seen you're reading the manual correctly, it does show flow going from the thermostat to the bottom of the radiator then out of the top radiator outlet to the pump.  Out of curiosity I checked the paper and pdf copies of my workshop manuals and there's no real guidance so all you have to go on is the parts manual.  I've got to be honest and say until this came up I'd never even thought about it, when I repaired my chassis I just followed what was there to start with.

What Chris describes is logical and how the Elan is plumbed, thermostat to top hose, bottom return into the engine pump so you'd expect the Europa to be the same. I suppose it depends if the pump is push or pull ? I've no idea if that matters, I'd have thought the pump pushes cooler water into the engine block but honestly I've no idea.

Equally possible is that there's been an error in the diagram for all these years and no-one has picked it up !  Intriguing whatever the reason, I might even go and see which hose in the front gets warm first !

Brian

[MRN I J]

every car in world that uses water / coolant uses the same system, cool coolant in to the bottom of the heat producer (the engine), heat is removed from the engine inc the thermostat at the top, either by pushing the coolant out or pulling the coolant out to the top of the heat dispenser, (the radiator), cooled coolant is then pulled or pushed from the bottom of the heat dispenser back into the bottom of the engine,
believe me I've been doing this mechanicing / engineering job for nearly 50 years now.

[Grumblebuns]

For some reason, the Europa does not appear to follow convention. I just pulled the coolant transfer tubes as part of my engine rebuild from my TCS and the layout is as per the parts manual.
- hot coolant comes out of the thermostat housing into the tube with the long bend (left hole in the chassis looking forward)
- enters the bottom of the radiator
- gets cooled and exits the top of the radiator into the tube (right hole in chassis)
- enters the engine at timing cover to water pump suction.

You can visually follow the layout by following the tubes from inside the access hole in the cabin

As an aside, the coolant transfer tube feeding coolant back to the engine was a bitch to remove. I had to remove the rear chassis cross beam to get enough room to pull it out. 

[MRN I J]

For some reason, the Europa does not appear to follow convention. I just pulled the coolant transfer tubes as part of my engine rebuild from my TCS and the layout is as per the parts manual.
- hot coolant comes out of the thermostat housing into the tube with the long bend (left hole in the chassis looking forward)
- enters the bottom of the radiator
- gets cooled and exits the top of the radiator into the tube (right hole in chassis)
- enters the engine at timing cover to water pump suction.

You can visually follow the layout by following the tubes from inside the access hole in the cabin

As an aside, the coolant transfer tube feeding coolant back to the engine was a bitch to remove. I had to remove the rear chassis cross beam to get enough room to pull it out.

So it defies the laws of physics that state hot water rises & vice versa

[Grumblebuns]

For some reason, the Europa does not appear to follow convention. I just pulled the coolant transfer tubes as part of my engine rebuild from my TCS and the layout is as per the parts manual.
- hot coolant comes out of the thermostat housing into the tube with the long bend (left hole in the chassis looking forward)
- enters the bottom of the radiator
- gets cooled and exits the top of the radiator into the tube (right hole in chassis)
- enters the engine at timing cover to water pump suction.

You can visually follow the layout by following the tubes from inside the access hole in the cabin

As an aside, the coolant transfer tube feeding coolant back to the engine was a bitch to remove. I had to remove the rear chassis cross beam to get enough room to pull it out.

So it defies the laws of physics that state hot water rises & vice versa

If a system has forced flow, it doesn't matter which way the coolant flows into the radiator. It so happens that the Europa goes against convention. Check it out yourself. The flow path is fairly easy to follow visually by noting which hole the pipes enter the chassis and exit the chassis. As I said earlier, look inside the chassis inspection hole under the center console to follow the pipe run.

 

[MRN I J]

I've just looked at the twin cam parts manual & you are right, the top thermostat housing connection feeds to the bottom of the radiator.
I admit this goes against everything i've been taught & have taught in the last 47 years about making efficient cooling systems.
I'll ask Paul Matty on Monday why they did this when they could have done it the theoretical correct way or I'll ask one of the designers who worked at Hethel from 69 to 74 & again 86 to 93 then again in 96, perhaps he'll know or he might be able to ask Mike Kimberley

[EuropaTC]

Perhaps one reason could be that it's not a conventional layout with (almost) horizontal steel tubes going the length of the car.   More heat will be lost during transmission to the rad than for a conventional system with shorter rubber hose connections. The temperature gradient will still play a part at the radiator itself but perhaps it's not as significant with this design.

Some cars (Elise) have the radiator mounted horizontally with inlet/outlet at the same level so as Grumblebuns says, with a forced flow system, providing your pump capacity is good enough the thermosyphon effect becomes less of an issue.

Brian
 

[Grumblebuns]

I am not an engineer but I have a little bit of knowledge of heat transfer and fluid flow remembered from my previous professional career. It takes a very specific set of conditions for natural convection or thermosiphon to occur and I can't think of any production car that was designed with any form of thermosiphon assistance as a design factor. When the water pump fails, the engine starts to heat up. If there is any thermosiphon, the mass flow rate and heat rejection from the radiator is too little to overcome the heat produced by the engine still running at road speed.

Looking at the cooling pipe layout in the parts manual, I'm wondering if the bends in the piping in order to be able to install/remove the pipe was what determined the direction of flow to the radiator. The S2 also has flow entering the radiator from the bottom.

[BDA]

I am led to understand that Henry Ford thought there should be a way to do away with a water pump but finally realized he couldn't.

I have to admit that I have never given the direction of coolant flow a whole lot of thought. So now I am giving it a bit of thought and I'm thinking that most of the heat comes from the head (right?) and it would seem to make sense to provide cooler water to it. Obviously, I'm missing something. Can someone explain what that is?

[Grumblebuns]

I'm not totally sure of the question but if you're asking how the coolant flows through the engine, this is my understanding for the twink:
- cooled coolant comes out of the top  of radiator through the transfer tubes into the timing chest cover front nipple
- through the timing chest cover passage into the water pump impeller located in front of #1 cylinder in the engine block cooling passage
- coolant is circulated into the block and up into the head through connecting passages
- hot coolant is discharged out of the thermostat housing back to the radiator bottom inlet.

I'm not sure if that is what you were asking for but makes sense to provide cool coolant from the bottom up.

 

[Roger]

There were quite a few thermosyphon-only cars way back, the Austin Seven for one. Water pumps were fitted to higher-output cars, and later to smaller radiators too.
I think the standard Europa radiator is a crossflow design, actually a twin crossflow. Water enters from the lower left, flows to the right, then upward to the top where it flows right to left and out again. There's a baffle between the two halves to keep it flowing the right way.

[BDA]

I'm not totally sure of the question but if you're asking how the coolant flows through the engine, this is my understanding for the twink:
- cooled coolant comes out of the top  of radiator through the transfer tubes into the timing chest cover front nipple
- through the timing chest cover passage into the water pump impeller located in front of #1 cylinder in the engine block cooling passage
- coolant is circulated into the block and up into the head through connecting passages
- hot coolant is discharged out of the thermostat housing back to the radiator bottom inlet.

I'm not sure if that is what you were asking for but makes sense to provide cool coolant from the bottom up.

Yes, I see that is the actual route the coolant takes. My question is: Since the heat in the engine is generated in the head, that seems like the part of the engine we should focus on cooling. So why wouldn't the cooling system be designed so that the coolest water goes there first? Such a design would work backwards from the way it actually works. The cooled water from the radiator would go to the head, down into the block, and out the water pump back to the radiator.

Since that is the opposite of the way it really works, I'm probably missing something pretty fundamental. Maybe the exhaust stroke pushes out enough heat that the block is actually the bigger concern?

[MRN I J]

I could ring Richard although I haven't spoken to him in 25 years