NG Fuel Pressure Regulator
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2002 Mercury Sable, 2002 Mercury Mountaineer, 2002 Mercury Grand Marquis, 2002 Mercury Cougar, and 2002 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
Fuel pressure regulator contains a 275 psi (1896 kPa) check valve that protects the low pressure system. When natural gas expands, fuel temperature decreases. Causing an extreme drop in temperature; to as low as -160°F (-177°C) . To prevent damaging synthetic fuel system components or causing water vapor within fuel to condense, engine coolant is routed through pressure regulator to warm fuel before it expands. The regulator has an internal thermostat to control flow of engine coolant, preventing overheating and thinning of fuel which could cause lean combustion. When coolant temperature increases to about 100°F (82°C), regulator thermostat closes and outlet coolant flow is restricted.