Faults of oil temperature sensor
- mechanical damage;
- incorrect sensor readings;
- lack of response.
Symptoms of oil temperature sensor failure
- error indicator on the instrument panel;
- engine overheating;
- excessive pressure in the engine lubrication system;
- loss of the vehicle maximum power;
- fuel and oil overconsumption;
- strange noise while the engine is running.
Causes of oil temperature sensor faults
- the sensor displacement;
- the thermistor degradation;
- use of low quality parts;
- intense temperature fluctuations;
- use of low-quality lubricants;
- low amount or complete lack of lubricant in the system;
- mechanical damage to the oil sump and related mechanisms.
Diagnostics
It is necessary first to test the contact integrity and the the sensor correct position in the system. Then, using a pressure gauge and an ohmmeter, measure key indicators. Oil pressure at low engine speeds should be near the mark of 2 bar. With increasing speeds up to 5000 it can increase up to 6 bar.
The electrical resistance of the item varies as the temperature increases. When the oil temperature is 0 °C, the resistance value should be 5-7 ohms. Maximum available oil temperature is 120 °C. At a higher value the lubricating properties are lost. The sensor resistance value at such oil temperature should be 150-220 ohms.
Checking the oil temperature sensor is performed during general diagnostics of the engine lubrication system. The optimal frequency is every 50 000-70 000 kilometers.
Replacing the oil temperature sensor
Repair of faulty sensor is not carried out due to the thermistor characteristics. Most often, the sensor is located at the bottom of the oil sump, but its exact location is necessary to look in the technical documentation of the vehicle.
First you need to choose the original or completely the same sensor. It is necessary to check that it is the right size. After draining the oil and removing the defective part a new one is installed, and the joints are treated with sealant. Be sure to check the correct wiring connection and its condition.
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