Lubricating Oil Filter Head - Rebuild (7-06) Section 7 - Lubricating Oil System - Group 07 M11 Page 7-10 Visually inspect the filter head for cracks or other dam- age. If cracks or damage is found, the filter head must be replaced. Visually inspect the thermostat and bypass valve for cracks or other damage. If the bypass valve is damaged, it must be replaced. Suspend the thermostat and a 116°C [240°F] thermom- eter in a container of new lubricating oil. Do not allow the thermostat or the thermometer to touch the sides of the container. Caution: The flash point of new lubricating oil is ap- proximately 221°C [430°F]. Do not allow the oil tem- perature in the container to exceed 149°C [300°F].
Do not allow water droplets to enter the container of hot oil. Water droplets will cause a violent reaction which can cause personal injury. Heat the lubricating oil. Write down the temperature at which the valve is fully extended. The valve must be fully extended to at least 6 mm [0.250 inch] from the closed position when the tem- perature reaches 115°C [240°F]. Replace the thermostat if it does not operate as described.