Talk Morgan Forums Morgan Sports Cars Morgan Photo Gallery Series 1 Roadster Cooling System

I’ve been trying to work out the cooling system on the Series 1 Roadster, and I think I’ve sorted it out in the rough drawing above.
The primary flow goes: Water Pump > Thermostat Housing > Engine > Water Pump
Then there’s: Water Pump > Thermostat Housing > Long Metal Pipe in middle of V > Top Hose > Radiator Header Tank > Small Bore Tube from Filler along nearside cylinder head > plastic Header Tank
And from the plastic Header Tank two flows:
One: to Heat Exchanger/Oil Filter > Water Pump
Two: to Heater upper tube > Heater > Heater lower tube > Engine > Water Pump
When the Thermostat finally opens, there is flow from the bottom of the Radiator > metal tube which runs under the nearside exhaust manifold > Thermostat Housing

This is why the Radiator Header Tank gets hot before the thermostat opens, and the plastic Header Tank displays a strong swirl from the small bore tube
I hope that makes sense.

I’ll go and lie down now.

PS Posted here to get an image big enough to read!!!!

Great piece of work Dave, I could not make sense of it myself, no wonder leaks are hard to find. I will put a copy in my file.

Nice Diagram Dave. Easy to follow.
I will check out the Jag when the snow clears.

Dave,
I was musing on if I could fit a shut off valve on the heater supply to try to reduce summer time cabin heat.

Any thoughts?
John

I don't see why it wouldn't work John. Mount it on the bulkhead and in the lower heater hose in the drawing between the heater and T piece. Old MG Midgets had a tap under the bonnet, and that's all it needs. You would just have to monitor the temp gauge a bit closer!!

Mine has a tap and a cross over piece too.

Thanks Dave. Yes my midget had the same.

Does anyone know of a normally open 16 mm solenoid valve. I was thinking of going upmarket & having a switch in the car to turn off the flow but I can only find normally off solenoid valves