[arcosine]

All cars use to have this feature, way back when, they have a thermostatic valve on the exhaust and hot exhaust would flow across the intake manifold during warm up. I think you could do this simply with one valve controlling the inlet coolant flow to a coil wrapped around the exhaust pipe. The valve is at the top of the tube. When the valve is off the coolant boils out of the tube like a vapor lock, no problem.