P1521–INCORRECT ENGINE OIL TYPE
When Monitored:
Engine Running.
Set Condition:
Using the oil pressure, oil temperature and other vital engine inputs the PCM can determine the engine oil
viscosity. Incorrect viscosity will effect the operation of the MDS by delaying cylinder activation.
Possible Causes
INCORRECT ENGINE OIL TYPE
ENGINE OIL CONTAMINATION
ENGINE OIL
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Review the customers oil change history. Make sure the customers is using the correct engine oil
viscosity. If the incorrect oil is being used, change the oil, using the correct engine oil viscosity.
Ignition on, engine off.
With the scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go to 2
No>>
Te s t C o m p l e t e .
2.ENGINE OIL
NOTE: If any engine oil pressure or oil temperature DTCs set along with P1521, repair them before continu-
ing with the P1521 diagnostics.
The following conditions must be checked.
OEM recommended oil viscosity is being used.
Customer is following the oil change schedule.
Check the engine oil for contamination. (i.e., fuel and/or engine coolant)
Internal engine condition that may effect oil pressure.
Were any of the above condition found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Change the engine oil using the correct oil viscosity.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES/LIFTERS 1. High or low oil level in crankcase 1. Check for correct oil level. Adjust
oil level by draining or adding as
needed
2. Thin or diluted oil 2. Change oil. (Refer to 9 -
ENGINE/LUBRICATION/OIL -
STANDARD PROCEDURE)
3. Low oil pressure 3. Check engine oil level. If ok,
Perform oil pressure test. (Refer to
9 - ENGINE/LUBRICATION -
DIAGNOSIS AND TESTING) for
engine oil pressure test/
specifications
4. Dirt in tappets/lash adjusters 4. Clean/replace hydraulic
tappets/lash adjusters
5. Bent push rod(s) 5. Install new push rods
6. Worn rocker arms 6. Inspect oil supply to rocker arms
and replace worn arms as needed
7. Worn tappets/lash adjusters 7. Install new hydraulic tappets/lash
adjusters
8. Worn valve guides 8. Inspect all valve guides and
replace as necessary
9. Excessive runout of valve seats
or valve faces9. Grind valves and seats
CONNECTING ROD NOISE 1. Insufficient oil supply 1. Check engine oil level.
2. Low oil pressure 2. Check engine oil level. If ok,
Perform oil pressure test. (Refer to
9 - ENGINE/LUBRICATION -
DIAGNOSIS AND TESTING) engine
oil pressure test/specifications
3. Thin or diluted oil 3. Change oil to correct viscosity.
(Refer to 9 - ENGINE/
LUBRICATION/OIL - STANDARD
PROCEDURE) for correct
procedure/engine oil specifications
4. Excessive connecting rod
bearing clearance4. Measure bearings for correct
clearance with plasti-gage. Repair
as necessary
5. Connecting rod journal out of
round5. Replace crankshaft or grind
journals
6. Misaligned connecting rods 6. Replace bent connecting rods
CONDITION POSSIBLE CAUSES CORRECTION
MAIN BEARING NOISE 1. Insufficient oil supply 1. Check engine oil level.
2. Low oil pressure 2. Check engine oil level. If ok,
Perform oil pressure test. (Refer to
9 - ENGINE/LUBRICATION -
DIAGNOSIS AND TESTING)
3. Thin or diluted oil 3. Change oil to correct viscosity.
4. Excessive main bearing
clearance4. Measure bearings for correct
clearance. Repair as necessary
5. Excessive end play 5. Check crankshaft thrust bearing
for excessive wear on flanges
6. Crankshaft main journal out of
round or worn6. Grind journals or replace
crankshaft
7. Loose flywheel or torque
converter7. Inspect crankshaft, flexplate/
flywheel and bolts for damage.
Tighten to correct torque
LOW OIL PRESSURE 1. Low oil level 1. Check oil level and fill if
necessary
2. Faulty oil pressure sending unit 2. Install new sending unit
3. Clogged oil filter 3. Install new oil filter
4. Worn oil pump 4. Replace oil pump assembly.
5. Thin or diluted oil 5. Change oil to correct viscosity.
6. Excessive bearing clearance 6. Measure bearings for correct
clearance
7. Oil pump relief valve stuck 7. Remove valve to inspect, clean
and reinstall
8. Oil pickup tube loose, broken,
bent or clogged8. Inspect oil pickup tube and pump,
and clean or replace if necessary
9. Oil pump cover warped or
cracked9. Install new oil pump
OIL LEAKS 1. Misaligned or deteriorated
gaskets1. Replace gasket
2. Loose fastener, broken or porous
metal part2. Tighten, repair or replace the part
3. Front or rear crankshaft oil seal
leaking3. Replace seal
4. Leaking oil gallery plug or cup
plug4. Remove and reseal threaded
plug. Replace cup style plug
DESCRIPTION - CRANKCASE BREATHER
The crankcase breather assembly is integrated into
the cylinder head cover (3) and is not serviced seper-
ately. The external fittings (2) to the breather tube and
breather drain tube are serviceable.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTION
LUBRICATING OIL
PRESSURE LOW1. Low oil level. 1. (a) Check and fill with clean engine oil.
(b) Check for a severe external oil leak that
could reduce the pressure.
2. Oil viscosity thin, diluted or wrong
specification.2. (a) Verify the correct engine oil is being
used. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION).
(b) Look for reduced viscosity from fuel
dilution.
3. Improperly operating pressure
switch/gauge.3. Verify the pressure switch is functioning
correctly. If not, replace switch/gauge.
4. Relief valve stuck open. 4. Check/replace valve.
6. If cooler was replaced, shipping
plugs may have been left in cooler6. Check/remove shipping plugs.
7. Worn oil pump. 7. Check and replace oil pump.
8. Suction tube loose or seal leaking. 8. Check and replace seal.
9. Loose main bearing cap. 9. Check and install new bearing. Tighten
cap to proper torque.
10. Worn bearings or wrong bearings
installed.10. Inspect and replace connecting rod or
main bearings. Check and replace directed
piston cooling nozzles.
CONDITION POSSIBLE CAUSES CORRECTION
11. Directed piston cooling nozzles
under piston, bad fit into main
carrier.11. Check directed piston cooling nozzles
position.
12. Loose oil rifle plug with saddle-jet
style nozzles12.Tighten oil rifle plug.
13. Loose directed piston cooling
nozzle.13. Tighten directed piston cooling nozzle.
14. Both J-jet and saddle jet style
cooling nozzle installed.14. Install correct style jet.
LUBRICATING OIL
PRESSURE TOO HIGH1. Pressure switch/gauge not
operating properly.1. Verify pressure switch is functioning
correctly. If not, replace switch/gauge.
ENGINE BREATHER
RESTRICTED2. Engine running too cold. 2. Refer to Coolant Temperature Below
Normal (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
3. Oil viscosity too thick. 3. Make sure the correct oil is being used.
(Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION).
4. Oil pressure relief valve stuck
closed or binding4. Check and replace valve.
LUBRICATING OIL LOSS 1. External leaks. 1. Visually inspect for oil leaks.Repair as
required.
2. Crankcase being overfilled. 2. Verify that the correct dipstick is being
used.
3. Incorrect oil specification or
viscosity.3. (a) Make sure the correct oil is being
used (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION).
(b) Look for reduced viscosity from dilution
with fuel.
(c) Review/reduce oil change intervals.
4. Oil cooler leak 4. Check and replace the oil cooler.
5. High blow-by forcing oil out the
breather.5. Check the breather tube area for signs of
oil loss. Perform the required repairs.
6. Turbocharger leaking oil to the air
intake.6. Inspect the air ducts for evidence of oil
transfer. Repair as required.
COMPRESSION KNOCKS 1. Air in the fuel system. 1. Identify location of air leak and repair. Do
not bleed high pressure fuel system.
2. Poor quality fuel or water/gasoline
contaminated fuel.2. Verify by operating from a temporary
tank with good fuel. Clean and flush the
fuel tank. Replace fuel/water separator filter.
3. Engine overloaded. 3. Verify the engine load rating is not being
exceeded.
4. Improperly operating injectors. 4. Check and replace misfiring/inoperative
injectors.
EXCESSIVE VIBRATION 1. Loose or broken engine mounts. 1. Replace engine mounts.
2. Damaged fan or improperly
operating accessories.2. Check and replace the vibrating
components.
OIL
STANDARD PROCEDURE
STANDARD PROCEDURE - ENGINE OIL LEVEL
CAUTION: Do not overfill crankcase with engine
oil, oil foaming and oil pressure loss can result.
To ensure proper lubrication of an engine, the engine
oil must be maintained at an acceptable level. The
acceptable oil level is in the SAFE RANGE (3) on the
engine oil dipstick.
1. Position vehicle on level surface.
2. With engine OFF, allow approximately 15 minutes
for oil to settle to bottom of crankcase, remove
engine oil dipstick.
3. Wipe dipstick clean.
4. Replace dipstick and verify it is seated in the tube.
5. Remove dipstick, with handle held above the tip, take oil level reading.
6. Add oil only if level is below the SAFE RANGE area on the dipstick.
7. Replace dipstick.
STANDARD PROCEDURE - ENGINE OIL SERVICE
WARNING: HOT OIL CAN CAUSE PERSONAL INJURY.
NOTE: Change engine oil and filter at intervals specified in the owner’s manual.
1. Operate the engine until the water temperature reaches 60°C (140°F). Shut the engine off.
2. Use a container that can hold at least 14 liters (15 quarts) to hold the used oil. Remove the oil drain plug and
drain the used engine oil into the container.
3. Always check the condition of the used oil. This can give you an indication of engine problems that might exist.
Thin, black oil indicates fuel dilution.
Milky discoloration indicates coolant dilution.
4. Clean the area around the oil filter head. Remove the filter (Refer to 9 - ENGINE/LUBRICATION/OIL FILTER -
REMOVAL).
5. Install new oil filter (Refer to 9 - ENGINE/LUBRICATION/OIL FILTER - INSTA L L AT I O N ) .
6. Clean the drain plug and the sealing surface of the pan. Check the condition of the threads and sealing surface
on the oil pan and drain plug.
7. Install the drain plug. Tighten the plug to 50 Nꞏm (37 ft. lbs.) torque.
8. Use only High-Quality Multi-Viscosity lubricating oil in the Cummins Turbo Diesel engine. Choose the correct oil
for the operating conditions (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES - DESCRIPTION).
9. Fill the engine with the correct grade of new oil (Refer to LUBRICATION & MAINTENANCE/FLUID CAPACITIES
- SPECIFICATIONS).
10. Start the engine and operate it at idle for several minutes. Check for leaks at the filter and drain plug.
11. Stop engine. Wait 15 minutes to allow the oil to drain back to the pan and check the level again.
USED ENGINE OIL DISPOSAL
Care should be exercised when disposing of used engine oil after it has beendrained from a vehicle’s engine.
CONDITION POSSIBLE CAUSES CORRECTION
CONNECTING ROD
NOISE1. Insufficient oil supply. 1. Check engine oil level.
2. Low oil pressure. 2. Check engine oil level. If OK, perform oil
pressure test. Inspect oil pump relief valve
and spring. (Refer to 9 - ENGINE/
LUBRICATION - DIAGNOSIS AND
TESTING).
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Measure bearings for correct clearance.
Repair as necessary.
5. Connecting rod journal out-of-
round.5. Replace crankshaft or grind journals.
6. Misaligned connecting rods. 6. Replace bent connecting rods.
MAIN BEARING NOISE 1. Insufficient oil supply. 1. Check engine oil level.
2. Low oil pressure. 2. Check engine oil level. If OK, perform oil
pressure test. Inspect oil pump relief valve
and spring. (Refer to 9 - ENGINE/
LUBRICATION - DIAGNOSIS AND
TESTING).
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Measure bearings for correct clearance.
Repair as necessary.
5. Excessive end play. 5. Check No. 3 bearing for wear on flanges.
6. Crankshaft journal out-of-round
and/or worn.6. Grind journals or replace crankshaft.
7. Loose flywheel. 7. Inspect crankshaft, flywheel, and bolts for
damage. Tighten bolts to correct torque.
OIL PRESSURE DROP 1. Low oil level. 1. Check oil level and fill if necessary.
2. Faulty oil pressure sending unit. 2. Replace sending unit.
3. Clogged oil filter. 3. Install new oil filter.
4. Worn oil pump. 4. Replace worn gears or oil pump
assembly.
5. Thin or diluted oil. 5. Change oil to correct viscosity.
6. Excessive bearing clearance. 6. Measure bearings for correct clearance.
7. Oil pump relief valve stuck. 7. Remove relief valve. Inspect valve and
spring. Replace as necessary.
8. Oil pump pick up tube restricted,
cracked, or damaged.8. Remove oil pan and inspect oil pump
pick up tube. Clean or replace as
necessary.
9. Oil pump cover loose, warped, or
cracked.9. Inspect/tighten cover screws or install
new oil pump, if necessary.
OIL LEAKS 1. Misaligned or deteriorated
gaskets.1. Replace gaskets.
2. Loose fastener, broken or porous
component.2. Tighten, repair or replace component.
12. Install oil fill cap.
13. Start engine and inspect for leaks.
14. Stop engine and inspect oil level. Adjust oil level as necessary.
OIL SPECIFICATION
DaimlerChrysler Corporation recommends a fully synthetic API certifiedengine oil of the proper viscosity grade for
refill. Viper engine factory fill is Mobil 1
10W-30 Synthetic.
OIL FILTER SPECIFICATION
All DaimlerChrysler Corporation engines are equipped with a high qualityfull-flow, disposable type oil filter.
DaimlerChrysler Corporation recommends a Mopar
or equivalent oil filter be used.
USED ENGINE OIL DISPOSAL
Care should be exercised when disposing used engine oil after it has been drained from a vehicle engine.