One draw-back to that method. It will work if everything on the engine is working perfect. But I was on a mali once where the tiny oil leak (supras are know for leaking in the back of the valve covers) was dripping on the exhaust and the oil smell was getting into the heater some how and it was chocking us to death. So any exhaust leaks or oil leaks would nix that method for me. Its just as simple to diy it and run it from the heater hose.