In at least some implementations, a fuel vapor separator for an internal combustion engine includes a main body at least partially defining a chamber for holding fuel, a lid carried by the main body to close the chamber and at least partially define a vapor chamber above a level of fuel in the chamber, and a thermoelectric heat exchanger coupled to the main body. In at least some implementations, the main body is a thermally conductive polymeric material that is resistant to degradation or dimensional changes, and in some implementations, the main body may be formed from a metal.