The present disclosure is directed to a system for reducing the cold start time for a vehicle with a twin fuel engine. The system has an exhaust system, from which exhaust is discharged and collected on an exhaust manifold. A heat exchanger is positioned within the exhaust system, with coolant flow passages in thermal communication with the engine, and the heat exchanger. A control valve is coupled to a first flow path operable to direct the exhaust through the heat exchanger across the first flow path and a second flow path in selective amounts.