I have a D6 9U and the air is being drawn thru and not blown thru the radiator. Is this normal? A friend said the fan is set up for winter operation and needs to be changed.

Normal operation was flow drawn through the radiator, blower fan (reverse) was an option.

Normally engines do suck air through the radiator by the way the fan fins are made. There is a fan that blows air through the radiator for summer operating. Older Cats you had to change the fan blade from suction to blower but in later years Cat made a fan assem. that you could turn the blade paddles in the opposite direction so you could set them for either blower or suction.I think where the blower fan came mostly into use was to keep the heat away from the operator in hot weather.