Normally the hot coolant feed to the heater core runs effectively in parallel to the thermostat bypass. Most vehicles (even my 52 year old Land Rover) have a simple in-line valve to control or completely turn off heat, so no need for bypass valve.

I shall be double checking this on my soon to arrive new Roadster, but assuming its installed as above, will simply add a generic heater control valve with cable operation to the interior, if there isn't one already.

ETA: I note the Roadster panels have two rotating contols in the centre with icons suggesting they control fan speed and heat output. Can anyone with a 3.7 Roadster confirm their function confused2

Last edited by Richard Wood; 31/07/18 07:12 AM.
Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone