My TC V8 has an MGB heater. It has no water control valve, and no power control. As a result, it's always on and blowing heat into the footwells. The guy who restored the car and put the TVR engine in it had overheating problems, so that may be why the heater is always on. When running, the temperature is a rock steady 80deg, so I'm happy with it.

What I don't know is whether the heater acts as part of the cooling system in the V8. In other words if I install an MGB water valve and close it, will I stop water from circulating through the rest of the system? Following hoses around the engine, I don't think so, but it's better to ask now than later.

My choices are: 1) install a water valve, 2) switch the fan or 3) run some flaps and ducting in the cockpit, to take the heat outside. Somehow.

4.
In reality there are many ways to run the cooling system. The best way to find out if the heater is part of the full flow system is to clamp the inlet pipe to stop flow and monitor the temp gauge.

Thanks Mel. In fact, I've tried a couple of things, and not got a conclusive result one way or another yet. It's not a seriously urgent problem, so I'll get stuck in again when I'm feeling braver.