843918 Volvo.Penta End plate

Introduction
Before you perform any procedure in this Special Instruction, read the information and understand the information that is contained in this instruction.This special instruction includes the recommended methods for determining fuel dilution of the engine oil. Additionally, the probable causes and the recommendation for correcting the fuel dilution are provided.Recommended Actions
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 is sometimes used to detect fuel dilution by measuring the volatile parts of the fuel that are remaining in the oil. Detecting less volatile components of the fuel that are left behind in the sump is more difficult and the accuracy of the flash test is reduced significantly.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 viscosityA significant level of fuel dilution reduces oil viscosity. Caterpillar SOS service's recommends a viscosity test for all diesel engine oils. The viscosity test must measure the kinematic oil viscosity in centistrokes (cSt) at 100° C (212° F). The result of the viscosity test is compared to SOS service's guidelines. A gas chromatograph is used in order to test for fuel dilution if the viscosity of the oil is below the guideline's value. The 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 a regional Caterpillar SOS lab. Some Caterpillar dealers also use a gas chromatograph. Even though the gas chromatograph provides a more accurate measure of fuel dilution the oil's viscosity should determine future actions and engine maintenance.Fuel dilution that is greater than four percent will usually cause viscosity that is less than the specified viscosity grade. For example, 15W-40 oil with four percent fuel dilution will have a viscosity of less than 12.5 cSt. The level of fuel dilution is higher in on-highway engines that are mandated for 2007 emissions requirements. The guidelines for fuel dilution have been changed in order to address the trends. Use the following chart to determine if viscosity has reached the minimum acceptable level. The guidelines of viscosity in the chart are slightly less than the limits of the SAE viscosity grades. However, these guidelines still provide adequate engine protection.
Table 1
Viscosity Grade     Oil Viscosity at (100 °C)     Percentage of fuel dilution     Action    
0W-40
5W-40
10W-40
15W-40
20W-40     Greater than 11.5 cSt     Less than 6     No Action is Required.    
Greater than 11.5 cSt Greater than 6     The oil must be sampled at the midpoint of the oil change interval and the oil must be sampled when the oil is drained. Reduce the interval of oil changes by 5 percent.    
Less than 11.5 cSt Greater than 6     Investigate the cause of fuel dilution. (1)Reduce the interval of oil changes by 10 percent. (2)    
0W-30
5W-30
10W-30     Greater than 8.5 cSt     Less than 6     No Action is Required.    
Greater than 8.5 cSt Greater than 6     The oil must be sampled at the midpoint of the oil change interval and the oil must be sampled when the oil is drained. Reduce the interval of oil changes by 5 percent.    
Less than 8.5 cSt Greater than 6     Investigate the cause of fuel dilution. (1)Reduce the interval of oil changes by 10 percent. (2)    
( 1 ) The SOS interpreter may recommend an inspection in order to determine the cause of the fuel dilution if values of viscosity are significantly below the values that are listed in the chart.
( 2 ) The SOS interpreter may recommend a shorter oil drain interval if the values for viscosity are slightly lower than the values that are listed in the chart.Verifying Fuel Dilution
Always verify the fuel dilution by the combination of low oil viscosity and gas chromatograph fuel dilution test result in excess of six percent before investigating or servicing the engine. Ask your dealership to submit an oil sample to a regional Caterpillar SOS lab for analysis if a gas chromatograph fuel dilution test cannot be performed at your dealership.Troubleshooting for Sources of Fuel Dilution
Use the following procedure to determine the locations of sources of fuel dilution around the electronic unit injectors under the valve cover.The tools that are required are listed below:
1U-5566 Ultraviolet Lamp Gp
1U-5575 Additive Dye
19 L (5 US gal) container for fuelNote: The engine must be at operating temperature or near operating temperature in order to perform this test.Note: Do not exceed 745 kPa (108 psi) of fuel pressure in the rail of the cylinder head when you pressurize the fuel system with a priming pump.
Add dye to the fuel in the container per the instructions for the dye and mix well.
Put the inlet and return lines for the fuel in the container with the fuel that contains dye.
Start the engine. Operate the engine until at least 11 L (3 US gal) of fuel is used or until the fuel that contains dye has returned to the container. Stop the engine.
Remove the valve covers.
Cap the fuel line and pressurize the fuel system with a priming pump.
Use the black light to inspect all of the unit injectors. A leak is indicated by a definite streak of fuel that contains dye at the leaking location.Leaking Seals on the Body or the Sleeve of the Unit Injector
Illustration 1 g01947082
(1) Fuel leakage is normal in these areas. Do not replace the fuel injector if fuel is leaking in this area. (2) Replace the fuel injector if fuel is leaking in this area. (3) Replace the O-rings if fuel is leaking in