GASKET 1397955 - Caterpillar

The engine oil temperature will be controlled by the regulating valve which is mounted on the front of the engine oil cooler. The regulators are designed to regulate the engine oil temperature to 75 °C (167 °F).Use the following procedure in order to measure the engine oil temperature.
Start the engine. Run the engine at low idle. Run the engine without a load.
Measure the engine oil temperature at the inlet of the engine oil cooler and at the outlet of the engine oil cooler. Also measure the engine oil temperature at the outlet of the regulating valve.
Run the engine at a known load until the engine oil temperature stabilizes.
Measure the engine oil temperature at the inlet manifold of the engine oil cooler and at the outlet manifold of the engine oil cooler. Also measure the engine oil temperature at the outlet of the regulating valve.
Compare the results.When the engine is operating at low idle, the regulators should be in the closed position. The engine oil should be bypassing the engine oil cooler. When the engine oil is bypassing the engine oil cooler, the temperature differential at the inlet of the engine oil cooler and at the outlet of the regulating valve should be close to zero. When the engine is operating under load, the engine oil is hot. The regulators are in the open position. Engine oil is forced through the engine oil cooler. When the engine oil passes through the engine oil cooler, the temperature differential at the inlet manifold of the engine oil cooler and at the outlet of the regulating valve increases. If the temperature differential is close to zero, the regulators are not operating. Replace the regulators.