gamoscoso

We have a 2011 Serrano with a Workhorse 7 FRED. So far ...so good. We can get 13.5 mpg if we drive under 65 mph. The engine is noisy only when you start rolling, especially up hills, once you pick-up speed, noise is low. If the OD kicks in on a steep climb, the two cooling fans go into high speed and make some strange noise. On a flat road @ 70 mph there is almost no noise. Heat from the engine does warm the cabin, you need to drive with the A/C full on, especially in hot weather.