Indeed this is not a Panda 750 by no means, and the radiator does do 95% of the work. The rear head often is the pain in the neck of the lazy mechanic because you have to remove the plenum and a bunch of extra components to access even the plugs, but I sincerely believe that it will always run at a higher temperature than the front one. Even by a bit more, it is common sense, if you move forward, no matter how many CFMs your fan will draw away, you still have air entering the engine at different speeds from the front of the car/underneath, so, by physics even if a little, the air will make a difference.That rear head is cooled in the same fashion than the front, but the heat buildup inside the engine compartment cannot be the same in the rear where you have the motor, the exhaust manifold, and a bunch of other components a few inches from the firewall the general temperature has to be higher, even by a few more degrees. In any case, no, you are correct, it does not purely cools by means of airflow, otherwise he would not have to check for oil in the coolant, because it would be an air cooled engine indeed.So, I may have been confusing and incorrect by saying that the rear head does not enjoy the air movement of the fan, what I meant was, the front head enjoys from a better life cycle than the rear because it is less neglected and is located at an advantageous location. In my small and limited experience, the rear head is the first to burn off the gasket, or leak for that matter because it does not get torqued down, the cover tightened as often as the front one, etc. At any rate, excessive smoke from the exhaust means you are either burning oil or coolant, depending on the smell of the smoke.