Lower Coolant Pipe

The Lower Coolant Pipe is an aluminum pipe which carries water from the radiator to the thermostat housing (via the lower radiator hose). While sometimes called the thermostat housing, this pipe should not be confused with the aluminum hard pipe assembly between the two cylinder heads which actually houses the thermostat while providing a passageway for hot coolant to flow to the radiator.
The main inlet on the pipe is 52mm in diameter.