To secure lubricating performance of an engine by certainly judging failure of an electric lubricating oil valve or an electric cooling water valve of a heat exchanger to cool lubricating oil with cooling water.

An electric cooling water valve WV is provided in a cooling water passage L10 connected to a heat exchanger HE, and an electric lubricating oil valve OV is provided in a lubricating oil passage L8 connected to the heat exchanger HE. When working quantity (valve opening quantity) of the electric cooling water valve WV and the electric lubricating oil valve OV is out of a specified range at the time when temperature of cooling water flowing in the heat exchanger HE or temperature of lubricating oil is stable, it is judged a failure such as short circuit and breaking of wire occurs. Additionally, when temperature of cooling water flowing in the heat exchanger HE or temperature of lubricating oil is not stable, it is judged a failure such as short circuit and breaking of wire occurs when an electric power value or a resistance value of the electric cooling water valve WV and the electric lubricating oil valve OV is out of a specified range.