ISSUE/CAUSE: Some vehicles equipped with the 6.0L diesel engine may exhibit diluted oil, runs rough and/or low
power. This may be caused by fuel leaking into the engine from the injectors.
• NOTE: THIS PROCEDURE MUST BE FOLLOWED COMPLETELY AND EXACTLY AS WRITTEN. FAILURE TO DO SO MAY RESULT IN MIS-DIAGNOSIS, INCOMPLETE REPAIR OR UNNECESSARY PART REPLACEMENT.
• Before starting the engine, check engine oil level on dipstick. If the oil level is above ‘max’ due to dilution with diesel fuel, the oil will appear thin and watery. Due to the design of the dipstick, it may be difficult to use for confirming an over full condition. If an over full condition is suspected, insert a clean dipstick leaving it one inch above the seated position.
Remove the dipstick and check the oil level. Continue this process, leaving the dipstick one inch higher each time. If the oil level is determined to be over full, pull the drain plug and let the oil/fuel drain out until it stops dripping (be sure to also drain the oil filter housing). Measure the amount of fluid drained from the crankcase.
• Note: For 6.0L Power Stroke diesel engines with engine oil diluted with four or more
quarts of diesel fuel, the turbocharger endplay needs to be checked (.001”- .004” allowable). Also check radial shaft movement by lifting the shaft up and rotating the shaft to check for compressor or turbine wheel housing contact. If any wheel contact is noticed, the turbocharger must be replaced.
• Check the PCM for Cylinder Contribution/Balance Diagnostic Trouble Codes (DTC’s). Diagnose Cylinder Contribution/Balance DTC’s per pinpoint test P15. Cylinder Contribution/Balance DTC’s will not be set for all injector related concerns resulting in fuel dilution. Continue with remaining steps.
• Block the fuel line to the left head at the fuel filter housing. To do this, remove the fuel line from the connection point at the secondary fuel filter housing. Remove the brass adaptor that is screwed into the filter housing. Remove the fuel pressure test port plug from the front of the secondary fuel filter housing. Install the plug in the left bank outlet port. The fuel pressure adaptor (#303-765) and fuel pressure gauge should be installed at the test port in order to confirm constant pressure.
• Run the fuel pump using WDS ‘Active Commands’ in order to maintain constant pressure.
• Watch for fuel to drain out of the oil pan drain hole. Depending on the severity of the leak, it may take some time to leak enough fuel to run down to the pan. Allow the fuel pump to run for up to 10 minutes.It is possible that the leak
indication may not occur when the engine is cold (cool). If this is the case, it will be necessary to perform the leak test on a warm engine. The block heater may be used to increase the coolant temperature to induce the leak if necessary in the case where the engine cannot be idled to warm-up prior to leak evaluation.
• If fuel is present suspect at least one injector or injector o-ring leaking in the right head.
Turn off the fuel pump at this time.
• Reverse the test at this time, blocking the right bank fuel line at the fuel filter housing.
Use the same procedure as described in step 3 (move the plug from the left supply port to the right bank supply port). It may also be necessary to loosen or remove the fuel line-retaining bolt secured to the front of the intake manifold.
• Run the fuel pump using WDS ‘Active Commands’.
• Watch for fuel to drain out of the oil pan drain hole. Depending on the severity of the leak, it may take some time to leak enough fuel to run down to the pan. Allow th efuel pump to run for up to 10 minutes.
• If fuel is present suspect at least one injector or injector o-ring is leaking in the left head. Turn off the fuel pump at this time.
Reconnect the fuel line.
• Remove the appropriate valve cover/s. If a fuel leak was not identified on the right or left bank, remove both valve covers for additional inspection.
• Remove the high-pressure oil rail. Check the torque of each injector hold down bolt. Refer to the Workshop Manual Section 303-04D for torque specifications. If an injector is found loose remove the injector. Inspect the injector body, injector body o-rings, and copper washer (at injector tip) for damage. Replace as necessary.
CAUTION: Installation and removal of an injector should not be completed with air/power tools. Excessive speed
can damage the injector o-rings.
• Clean the top of the head with brake clean and dry it thoroughly especially on the down side of each injector.
• Turn on the fuel pump. Inspect injector body o-ring area. Look carefully to see if fuel is leaking from the small weep hole just above the top injector body o-ring. Use a mirror to help look for fuel leaking from individual injectors. If a leak is not detected within 5 minutes, install 1 oz. of oil dye and continue your inspections.
Note: Adding 1 oz. of oil dye to the fuel filter housing in conjunction with use of a black light may aid in identifying
the fuel leak.
• If fuel is observed leaking from the injector body o-ring area replace the two injector body o-rings. If fuel is leaking from the small weep hole just above the top injector body o-ring replace the injector.
CAUTION: Installation and removal of an injector should not be completed with air/power tools. Excessive speed
can damage the injector o-rings.
• Following any repair, retest to confirm repair.
• Check the Charge Air Cooler (CAC) for fuel and/or oil. Clean the CAC and air dry with shop air thoroughly before
reinstalling.
• Re-install the oil pan drain plug. Refill engine with oil and change oil filter.
• Drive vehicle approximately 20 miles.
• Change engine oil and filter. Be sure to drain the oil out of the oil filter housing. Repeat final steps (maximum of two engine oil flushes).