Multi-layer liquid-cooled mount

An exhaust after-treatment system for treating an exhaust produced by an engine. The exhaust after-treatment system may include an exhaust passageway in communication with the engine, and an exhaust treatment component provided in the exhaust passageway. A dosing module for dispensing an exhaust treatment fluid into the exhaust passageway can be located between the engine and the exhaust treatment component. A coolant source and a modular liquid-cooled mount for supporting and cooling the dosing module is also provided. The liquid-cooled mount communicates with the coolant source and includes an inlet sub-mount including a first coolant passageway, a base sub-mount including a second coolant passageway, and at least one intermediate mount disposed between the inlet sub-mount and the base sub-mount that includes a third coolant passageway, wherein each of the first, second, and third coolant passageways are in communication with each other.