A question

[JOWETTJAVELIN]

Is the sidevalve engine cooling by thermo-siphon?

[smithskids]

Yes but you can get a pump and thermostat as was fitted to later engines.

[JOWETTJAVELIN]

Thanks.

[mike.perry]

There were two designs of engine for the Series MM, Type USHM2 was thermosyphon cooled with no provision for a water pump. Type USHM3 was also thermosyphon cooled but had a different cylinder head and other accessories including a blanking plate on the front of the block which could be removed to fit a water pump to provide water circulation for a heater

[JOWETTJAVELIN]

Thanks Mike it was the subject of heaters I was pondering.

[mike.perry]

There is a water pump available for the earlier engine which drives off the outside of the fan belt. I have the instructions.

[oliver-morrisminor]

If it is any help apparently there are
12volt electric water pumps available
these days, but i don't know what they
look like or how succesful theuy are.

[katy]

Speaking of 12 volt pumps, our 2000 Chevrolet mini-van has one, factory fitted, in-line w/the heater, runs any time the heater fan is switched on. Runs quiet.