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MG Midget and Sprite Technical - Water flow

Hi Chaps...here's today's dumb question:-
I have a 1275 with a vertical flow radiator. It has a heater coz l'm a wuss..
What puzzles me concerns the water pipes and hoses in as much as which direction is water flowing in them when we're up and running...
Told you it was a dumb question, but, anybody?
Thanks, Dave
David Cox

Water/coolant flows out of the thermostat housing to the radiator and back in to the water pump.

As far as the heater is concerned, the coolant flows out of the back of the cylinder head, through the heater matrix and back into the bottom hose, where it goes back into the engine.
Dave O'Neill 2

Thanks Dave. Makes sense, thinking about it. So the flow into the heater matrix comes about by thermo-syphon effect??
Dave
David Cox

The heater flow is not thermosiphon, the heater inlet flow is taken from the back of the head which is pressurised by the water pump and the outlet connects to the pump inlet so there is a pressure differential causing flow.
David Billington

Thanks. It seems you have to be called David to have any interest in this๐Ÿ˜
David Cox

Sorry David I was distracted elsewhere.

Interesting Q, tells me a lot too, you were not alone, wondering.
Bill sdgpM

I think we all thought Dave O answered it, and then we went with the flow. ๐Ÿ˜†
anamnesis

This thread was discussed between 30/08/2025 and 01/09/2025

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