Models equipped with Twin-Cooling do not use an oil cooler.
The flow of oil to the cooler is controlled by a thermostat in an adapter located between the oil filter and the filter mount.
Pressurized oil flows from the oil filter mount into a passage in the oil cooler adapter. The thermostat is located between the supply and return ports of the adapter. It consists of a temperature sensitive element compressed between a spring and a threaded plug.
When the engine oil temperature is below 200 °F (93 °C), the thermostat is open. This allows the largest percentage of oil to pass from the supply port to the return port. From the return port, oil flows to the oil filter. A smaller percentage flows through the oil cooler.
When oil temperature exceeds 200 °F (93 °C), the thermostat closes. This causes all the oil to flow to the oil cooler. Oil circulates through the finned tubes of the cooler to dissipate heat.
Oil then returns to the cooler adapter through a return hose.
The oil is then filtered before returning to the crankcase.
NOTE
Regardless of whether the thermostat is closed or open, oil is always pressurized in the oil cooler adapter, the oil cooler supply hose, the oil cooler and the oil return hose.
Check the oil cooler fins for dirt and debris at every service interval.
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