The fact that I understand they mean cooler.....doesn't mean its that cool.....only a few degree lower then standard and it certainly help to produce more power......what you mean by lower is the engine fail to warm up properly and not in the proper working temp but thats not what we mean by cooler engine......I understand you try to explain if the engine is not in proper working temperature it will increase fuel consumption....but by putting thermo and fan switch will only prolong the life of the engine but not doing any harm of it......