Answer: There is a thermal control valve at the front end of the oil cooler. If the oil temperature rises above 67℃, it will slowly open and fully open at 72℃. At this time, the lubricating oil will enter the body after being cooled by the oil cooler. When it fails, the lubricating oil will not pass through the oil cooler, so the temperature will slowly rise and shut down.
The common cause of failure of the thermal control valve during operation is sticking due to carbon deposits. The maintenance method only requires removing the valve core and using carbon deposit cleaning agent to clean the carbon deposits.