CAP-FUEL 4509357 - Caterpillar

Table 1
Diagnostic Trouble Codes for Oil Contains Fuel
J1939 Code Description Notes
5055-17 Engine Oil Viscosity : Low - least severe (1) The Electronic Control Module (ECM) calculates that the amount of fuel in the engine oil is high.
If equipped, the warning lamp will come on.
5055-18 Engine Oil Viscosity : Low - moderate severity (2) The ECM detects that the amount of fuel in the engine oil is very high.
If equipped, the warning lamp will flash. The engine will be derated. The engine ECM calculates the amount of fuel in the engine oil based on the engine operating conditions and the number of Diesel Particulate Filter (DPF) active regenerations since the last time the "Engine Oil Life Reset" was performed.Note: Before continuing with this procedure, ensure that the engine oil has been changed according to the maintenance schedule. Refer to Operation and Maintenance Manual, "Maintenance Interval Schedule". If the engine oil has been changed, ensure that the "Engine Oil Life Reset" is performed. Refer to Operation and Maintenance Manual, "Engine Oil and Filter - Change".Measuring Fuel Dilution
Diesel fuel is chemically similar to the lubricants that are used in diesel engines. A slow fuel leak will blend the fuel into the oil. Normal operating temperatures may cause volatile parts of the fuel to vaporize. The fuel that remains in the oil is less volatile.A closed cup flash test can be performed in order to detect fuel dilution. The flash test is designed to measure the volatile parts of the fuel that are remaining in the oil. Detecting less volatile fuel is difficult. The less volatile fuel reduces the accuracy of the flash test.Since the flash test does not accurately detect fuel dilution, do not use the flash test as the only measure of fuel dilution. Instead, verify the dilution by the following methods:
Gas chromatograph fuel dilution test
Oil viscosityThe test that uses a gas chromatograph is designed to measure fuel dilution in crankcase oils. The gas chromatograph can identify the small chemical differences between diesel fuel and lubricating oil. A gas chromatograph is used to measure fuel dilution at all Caterpillar regional SOS laboratories. Some Cat dealers also use a gas chromatograph. Even though the gas chromatograph provides a more accurate measure of fuel dilution, always verify the results with the viscosity test.A significant level of fuel dilution reduces oil viscosity. If an unacceptable level of fuel dilution is suspected, the kinematic viscosity of the oil must be measured.Fuel dilution that is greater than 10 percent will usually cause viscosity that is less than the specified viscosity grade. If the oil is still within the specified viscosity grade, fuel dilution has not reached an unacceptable level.Verifying Fuel Dilution
Verify fuel dilution by the combination of low oil viscosity and a gas chromatograph that gives a result in excess of 10 percent before investigating or servicing the engine. Ask the Cat dealer to submit an oil sample to a Caterpillar regional SOS laboratory for analysis if a fuel dilution test cannot be performed locally.Probable