In the Husqvarna line, when you get up to the large frame Z's (52" and up) they hydro system changes over to a system with a 2 qt capacity. I has 2 qts of mobil 1 synthetic with a cooler. That would reduce changing costs a lot But.... The small frames have a 2 gallon 20W-50 system, no cooler. Now 2 quarts??? Even with a cooler is that enough fluids?