What coolant do the previous gen Ford Taurus use? A guy at work asked me to check his cars coolant because the interior heater is blowing lukewarm. I took off the overflow tank cap and the tank is full of sludgy brown soup. It didn't look as orangey or clumpy as the huge dexcool mess that wrecked my Northstar engine. I have never owned a Ford. The Taurus radiator appears to have no cap at all, or maybe you have to remove a crossmember to access a well hidden one.