[DeTomaso] Complete coolant flush?

[David Moretto]

Thanks to all for your suggestions.

I drained my coolant to get a base line on the oil/coolant issue.

The manual instructs to open petcock on the bottom of the radiator and remove the pressure cap on the supply tank.

When I did that I only captured a little over 2 gallons of coolant. 

The manual states there is 6 3/8 gallons in the system.

I understand there is water trapped behind the closed thermostat and water in the heater line but 4 gallons and change?  

What is the easiest way to drain ALL of my coolant?

David