Exhaust after treatment cooling system

A cooling system for a tractor exhaust after treatment, the cooling system comprising:

• an exhaust system comprising an exhaust pipe and a catalytic converter;
• a urea dosing module configured to inject urea into the catalytic converter, the urea dosing module having a first port and a second port;
• an engine cooling system comprising:
• a heat exchanger;
• a fan;
• a coolant pump;
• a coolant feed line connecting the heat exchanger to the first port, the coolant feed line comprising first and second vertical feed pipe sections connected by a U-shaped section, wherein ends of the U-shaped section of the coolant feed line are directed downward, and wherein the second vertical feed pipe section is connected to the first port;
• and
• a coolant return line connecting the second port to the heat exchanger, the coolant return line comprising first and second vertical return pipe sections connected by a U-shaped section, wherein ends of the U-shaped section of the coolant return line are directed downward, and wherein the first vertical return pipe section is connected to the second port;
• wherein each of the first and second vertical feed pipe sections and the first and second vertical return pipe sections are oriented longitudinally parallel to an axis C substantially vertical relative to ground;
• and
• a bypass line connecting the U-shaped section of the coolant feed line to the U-shaped section of coolant return line;
• wherein at least one pipe section selected from the group consisting of the second vertical feed pipe section and the first vertical return pipe section extends upward from the urea dosing module.