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Caterpillar C18-C Engine

The Caterpillar C18-C is a 18 L turbocharged engine rated at 2100 rpm. It powers generator sets from Northern Lights, including the M843JK.

Also known as: Caterpillar C18-C

Part of the Caterpillar C18 engine family — 8 variants share parts & fitment.

18.0 L
Displacement
2100 rpm
Rated speed

Engine specifications

Displacement18.0 L
AspirationTurbocharged
Rated speed2100 rpm

Common problems

15
  • Engine Hard to Start or Will Not Start
    Cause: Improper starting procedure
    Fix: See starting section of this manual. Take special note of Bypass Switch operation.
  • Lack of Engine Power
    Cause: Intake air restriction
    Fix: Service air cleaner.
  • Engine Runs Irregularly or Stalls Frequently
    Cause: Below normal engine temperature
    Fix: Remove and check thermostat.
  • High Fuel Consumption
    Cause: Improper type of fuel
    Fix: Use correct fuel for temperature.
  • Engine Overheats
    Cause: Low coolant level
    Fix: Fill tank or radiator to proper level; Check hoses for loose connections and leaks.
  • Starter Cranks Slowly
    Cause: Low battery output
    Fix: Battery is too small; Battery cables are too small.
  • Engine Emits Black or Gray Exhaust Smoke
    Cause: Clogged or dirty air cleaner
    Fix: Service air cleaner.
  • Starter Inoperative
    Cause: Check DC circuit breaker
    Fix: If the breaker is tripped, reset it.
  • Engine Knocks
    Cause: Insufficient oil
    Fix: Call your dealer.
  • Engine Emits White Smoke
    Cause: Improper fuel
    Fix: Use correct fuel for temperature.
  • Low Oil Pressure
    Cause: Low oil level
    Fix: Fill crankcase to proper level.
  • High Oil Consumption
    Cause: Break-in period
    Fix: Oil consumption decreases after break in.
  • Entire Electrical System Does Not Function
    Cause: Check DC circuit breaker
    Fix: If breaker is tripped, reset it.
  • Battery Will Not Charge
    Cause: Loose or corroded connections
    Fix: Clean and tighten battery connections.
  • Below Normal Engine Temperature
    Cause: Thermostat not working properly
    Fix: Check thermostat.

Compiled from service & troubleshooting documentation across every generator set that uses the Caterpillar C18-C.

Service intervals

18
ItemActionHoursMonthsNotes
Battery electrolyteCheck50 hr1 moFirst service — After first 50 hours; check every 50 hours or once per month
Cylinder head boltsAdjust50 hrFirst service — Retighten after first 50 hours
V-belt tensionCheck50 hrFirst service — After first 50 hours
ValvesAdjust50 hrFirst service — After first 50 hours
Batteries, cables and terminalsClean100 hrCheck and clean every 100 hours
Radiator finsClean100 hrIndustrial only; clean in very dusty applications
Air cleanerCheck200 hrEvery 200 hours; more often in dusty conditions
Engine oil and filterChange200 hrFirst service — Every 200 hours
Exhaust elbowInspect200 hrEvery 200 hours; check for corrosion and exhaust leakage
Primary fuel filter element (Racor)Change200 hrEvery 200 hours or as necessary
Secondary fuel filterChange200 hrEvery 200 hours
BatteriesTest600 hrCheck condition with hydrometer every 600 hours
Cooling systemClean600 hr12 moFlush every 600 hours or every 12 months, whichever comes first
InjectorsCheck600 hrEvery 600 hours by dealer or injection repair station
Raw water pump impellerReplace600 hrMarine only; every 600 hours or as needed
Valve clearancesCheck600 hrEvery 600 hours
Fuel injection pumpCheck2400 hrEvery 2400 hours
Heat exchangerClean2400 hr12 moMarine only; once a year or after 2400 hours

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

25
TypeItemValueUnitCondition
ClearanceV-belt deflection3/16inmidpoint between crankshaft and alternator pulleys
ClearanceV-belt deflection5mmmidpoint between crankshaft and alternator pulleys
PressureCoolant filler cap pressure valve0.5bar
PressureCoolant filler cap pressure valveapproximately 7PSI
PressureOil pressureabove 15PSIoperating
PressureOil pressure after a few seconds of operation20-60PSInormal reading
TemperatureIndustrial shutdown temperatureabove 110°Cshut off engine immediately
TemperatureIndustrial shutdown temperatureabove 230°Fshut off engine immediately
TemperatureMarine shutdown temperatureabove 205°Fshut off engine immediately
TemperatureMarine shutdown temperatureabove 96°Cshut off engine immediately
TemperatureWater temperature gauge (industrial)below 107°Coperating
TemperatureWater temperature gauge (industrial)below 225°Foperating
TemperatureWater temperature gauge (marine)below 200°Foperating
TemperatureWater temperature gauge (marine)below 94°Coperating
TorqueCylinder head bolts60 - 64ft/lbscold
TorqueCylinder head bolts9.0 - 9.5kg/mcold
TorqueDelivery lines at injectors11-18ft./lbs
TorqueInjector44 - 51ft/lbs
TorqueInjector6 to 7kgm
TorqueReturn line retaining bolts22 - 30ft/lbs
TorqueRocker arm cover nuts0.8 - 2.3kg/m
TorqueRocker arm cover nuts5 - 8ft/lbs
Valve clearanceIntake and exhaust valve clearance0.008incold, engine not running
Valve clearanceIntake and exhaust valve clearance0.2mmcold, engine not running
VoltageDC voltmeter11 - 15volts80°F (25°C) ambient temperature

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

FluidGradeStandardAmbientCapacityNotes
Coolant50% distilled water / 50% ethylene glycol antifreeze mix4.1 litersRecommended as a good year-round coolant; approx cooling capacity HE 1.1 gal (4.1 liter)
Engine oilSAE 5-20WAPI Service CC/CD/SF multi-viscositybelow -23°CBelow -10°F (-23°C)
Engine oilSAE 5WAPI Service CC/CD/CE single viscositybelow -23°CBelow -10°F (-23°C)
Engine oilSAE 10-30WAPI Service CC/CD/SF multi-viscosity-23°C to 0°C-10 to 32°F (-23 to 0°C)
Engine oilSAE 10WAPI Service CC/CD/CE single viscosity-23°C to 0°C-10 to 32°F (-23 to 0°C)
Engine oilSAE 15-40WAPI Service CC/CD/SF multi-viscosityabove 0°CAbove 32°F (0°C)
Engine oilSAE 30WAPI Service CC/CD/CE single viscosityabove 0°CAbove 32°F (0°C)
FuelNo. 1 dieselASTM D975below 0°CBelow freezing and all temperatures at altitude above 5,500 ft. (1500 meters)
FuelNo. 2 dieselASTM D975above 0°CAbove freezing 32°F (0°C); sulphur less than 1% (preferably less than 0.5%); cetane minimum 45

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

12
Valve Clearances adjustment

⚠ Engine should be cold and NOT running.

Tools: Feeler gauge, Wrench

  1. Adjust valve clearance after first 50 hours and every 600 hours thereafter.
  2. Do adjustment after cylinder head bolts have been retightened; engine cold and NOT running.
  3. Turn engine by hand until inlet valve starts to open and exhaust valve starts to close; turn one more full turn.
  4. Loosen lock nut and adjust clearance between rocker arm and valve guide to 0.008 in. (0.2 mm).
  5. Repeat for each cylinder; replace rocker arm cover and tighten cover nuts to 5 - 8 ft/lbs.
Air Cleaner Service maintenance

⚠ Do NOT run the engine with the air cleaner removed.

  1. Inspect air cleaner every 200 hours; check more often in dusty conditions.
  2. Marine: if dirty, wash element in soapy water; rinse and dry thoroughly before reinstalling.
  3. Marine: replace element if necessary.
  4. Industrial: element cannot be cleaned; replace when necessary.
  5. Make sure no impurities enter engine while changing element.
Battery Care maintenance

⚠ Battery gas can explode; keep flames and sparks away from batteries.

Tools: Hydrometer

  1. Check electrolyte level every 50 hours or once per month; add distilled water to manufacturer's recommended level.
  2. Check and clean batteries, cables, and terminals every 100 hours.
  3. Clean corrosion with water and baking soda solution; flush with clean water.
  4. Tighten terminals and grease them to inhibit corrosion.
  5. Check battery condition with a hydrometer every 600 hours.
Bleeding the Fuel System maintenance

⚠ Escaping diesel fuel under pressure can penetrate skin causing serious personal injury.

⚠ Use cardboard or wood, not hands, to search for suspected leaks.

Tools: Wrench

  1. Loosen bleed bolt A on top of the filter.
  2. Pump hand primer B on fuel lift pump until pure fuel without bubbles escapes from bleed bolt A; tighten A.
  3. Loosen bleed screw C; pump hand primer B until pure fuel escapes; tighten C.
  4. If engine does not start, loosen a fuel line at the injector while cranking until pure fuel escapes; tighten connection.
  5. After engine starts, use cardboard to look for fuel leaks.
Changing Lube Oil Filter maintenance

⚠ Overtightening can damage the filter housing.

Tools: Filter wrench

  1. Use a filter wrench to remove old filter; discard in approved manner.
  2. Remove and discard old filter gasket; clean mount face.
  3. Spread thin film of engine oil on new filter gasket.
  4. Screw filter on until gasket meets sealing surface.
  5. Tighten one-half turn farther by hand only.
  6. Fill engine with recommended oil; start and check for leakage.
  7. Stop engine, wait 3 minutes, and check oil level; add oil if necessary.
Cooling System Flushing maintenance

⚠ Allow engine to cool before working on cooling system.

⚠ Open filler cap carefully using protective clothing when engine is warm.

  1. Flush cooling system every 600 hours or every 12 months, whichever comes first.
  2. Marine: remove expansion tank cap and drain engine block.
  3. Marine: open block drain cock and remove hose from bottom of heat exchanger tank.
  4. Marine: flush with clean water until drains are free of discoloration and sediment; drain completely and refill with recommended mixture.
  5. Industrial: remove radiator cap and open drain cocks on radiator and engine block.
  6. Industrial: flush until water is clear; drain completely and refill with recommended coolant mixture; clean radiator fins.
  7. Check hoses and connections and repair any leakage.
Engine Oil Change maintenance

⚠ Never use flushing oil or additives in crankcase.

⚠ Dispose of waste oil in an approved manner.

Tools: Oil drain container

  1. Change engine oil and oil filter after first 50 hours; use Service CC 30 weight oil during first 100 hours.
  2. Change oil and filter again at 100 hours; thereafter change every 200 hours.
  3. Warm engine, loosen clamp on oil change tube, remove cap, and drain oil.
  4. Replace cap and tube; refill with recommended oil for the season.
Fuel Filter Replacement maintenance

⚠ Do not overtighten.

Tools: Filter wrench

  1. Remove spin-on filter by turning counterclockwise with a filter wrench.
  2. Fill new cartridge with fuel and apply engine oil to gasket surface.
  3. Screw on until gasket surface contacts sealing surface of filter base.
  4. Tighten two-thirds of a turn by hand; do not overtighten.
Raw Water Pump Impeller Replacement maintenance

⚠ Place protection under screwdrivers so pump housing is not damaged.

⚠ Keep an extra impeller and cover gasket in reserve on board.

Tools: Needle-nose pliers or two screwdrivers

  1. Change seawater pump impeller every 600 hours or as needed.
  2. Remove pump end cover.
  3. Pry out impeller using needle-nose pliers or two screwdrivers.
  4. Remove all pieces of failed impeller and clean inside of housing.
  5. Press in new impeller and place sealing washers in outer end of impeller center.
  6. Replace cover using a new gasket.
Retightening Cylinder Head Bolts maintenance

Tools: Torque wrench

  1. Tighten bolts when the engine is cold.
  2. Loosen nuts and remove rocker arm cover.
  3. Tighten head bolts with a torque wrench in the order shown.
  4. Tighten evenly in 2 or 3 passes, ending at specified torque in final pass.
Winterizing / Out-of-Service maintenance

⚠ Store set in a dry, protected place; if stored outside, protect with a cover.

  1. Marine: drain fresh water and seawater cooling systems completely; shut off seacocks before opening drain cocks.
  2. Marine: drain water supply lines and wet exhaust line; loosen seawater pump cover and drain pump.
  3. Industrial: drain and flush radiator and cooling system; leave dry or refill with antifreeze-water mixture.
  4. Industrial: fill fuel tank or add biocide; seal air cleaner inlet, exhaust opening, crankcase breather pipe, and fuel tank vent.
  5. Marine and industrial: change crankcase oil and filter; loosen alternator belt.
  6. Disconnect and clean battery; remove to warm storage if possible.
  7. Clean outside of unit; paint scratched or chipped surfaces; apply corrosion preventative to exposed metal.
Before Starting operation

⚠ Use protective clothing and open the filler cap carefully when the engine is warm to prevent burns.

⚠ The battery switch must always be kept ON while the engine is running.

  1. Check coolant level about 1 in. (2.5 cm) below filler cap sealing surface when cold.
  2. Check crankcase oil with dipstick; level must be in waffled area.
  3. Check fuel tank level and open any fuel valves.
  4. Marine: close sea-cock; clean sea strainer; reopen sea-cock.
  5. Marine: place battery switch in ON position and keep it ON while running.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Parts cataloged across the Caterpillar C18 family

107
Part #DescriptionCategory
106-3973Air filter innerAir filter
151-7737Air PrimaryAir filter
189-0202Air SecondaryAir filter
1W-3636Air SecondaryAir filter
1W-3637Air PrimaryAir filter
246-5009AirAir filter
246-5010AirAir filter
4N0015Air filter outerAir filter
7C-1571Air PrimaryAir filter
8N6309Air filter outerAir filter
9Y-3879AirAir filter
6T1395AlternatorAlternator
118-2018V-beltBelt
4N6302V-beltBelt
M-CK3687817PCylinder KitCylinder kit
133-5673Fuel/Water SeparatorFuel filter
1R-0749Fuel Secondary - ADVFuel filter
1R-0762Fuel Secondary - ADVFuel filter
1R-0770Fuel/Water SeparatorFuel filter
1R-0781Fuel/Water Separator - ADVFuel filter
1R0749Filter fuelFuel filter
1R0755Filter fuelFuel filter
326-1641Axial seal FWSFuel filter
326-1642Filter water separatorFuel filter
326-1643Filter water separatorFuel filter
3S3875Filter fuelFuel filter
9N3717Filter water separatorFuel filter
4N1151Gasket oil panGasket
M-4220925Gasket Set - Rear StructureGasket
M-4337629Gasket Set - Rear StructureGasket
M-4351087Gasket Set - Rear StructureGasket
M-4361559Gasket Set - Front StructureGasket
M-4365757Gasket Set - Turbo InstallationGasket
M-4452666Gasket Set - Rear StructureGasket
M-4496052Gasket Set - Oil Cooler & LinesGasket
M-4588198Gasket Set - Front StructureGasket
M-4682161Gasket Set - Cylinder HeadGasket
M-4685553Gasket Set - Central & LowerGasket
M-4685746Gasket Set - Cylinder HeadGasket
M-4687363Gasket Set - Water PumpGasket
M-4687942Gasket Set - Turbo InstallationGasket
M-4690626Gasket Set - Central & LowerGasket
M-4690822Gasket Set - Turbo InstallationGasket
M-4690823Gasket Set - Cylinder HeadGasket
M-4690878Gasket Set - Cylinder HeadGasket
M-4692381Gasket Set - Central & LowerGasket
M-4692382Gasket Set - Fuel SystemGasket
M-4692388Gasket Set - Cylinder HeadGasket
M-4701892Gasket Set - Turbo InstallationGasket
M-4733264Gasket Set - Rear StructureGasket
M-4886213Gasket Set - Oil CoolerGasket
M-4916359Gasket Set - Turbo InstallationGasket
MCB3306031MAJOR OVERHAUL GASKET SETGasket
MCB3306032GASKET SETGasket
MCB3306033CYLINDER HEAD GASKET SETGasket
MCB3306121MAJOR OVERHAUL GASKET SETGasket
MCB3306122GASKET SETGasket
MCB3306123CYLINDER HEAD GASKET SETGasket
M-2572752Gasket Set - C18 Front StructureGasket set
M-3604170Gasket Set - C18 Front StructureGasket set
M-3605916Gasket Set - C18 Central & LowerGasket set
M-4154993Gasket Set - Single Cylinder Head - C18Gasket set
M-4446485Gasket Set - C13-C15-C18 Front StructureGasket set
126-1815Hydraulic - UHEHydraulic filter
144-6691HydraulicHydraulic filter
1R0774Filter hydraulicHydraulic filter
328-3655Filter hydraulic/transmissionHydraulic filter
9T0973Filter hydraulic/transmissionHydraulic filter
M-2463129Impeller – Water PumpImpeller
102-2828Filter oilOil filter
1R-0716Engine OilOil filter
1R-1808Engine Oil - ADVOil filter
1R0716Filter oilOil filter
1R1808Filter oilOil filter
2243245Connecting rodService part / kit
249-0439Oxidation Catalyst Assembly - RoundService part / kit
256-0331Oxidation Catalyst Assembly - RoundService part / kit
385CHydraulic ExcavatorService part / kit
888-983-7847ENGINE BLOCK CRANKSHAFTService part / kit
A100Download SpecificationService part / kit
AEXQ1051-00Not explicitly stated in the document.Service part / kit
M-3687815PistonService part / kit
M-3687816PistonService part / kit
M-CK3687815PKit - Cylinder KitService part / kit
M-CK3687816PKit - Cylinder KitService part / kit
PEDJ0512-01Ripper – Single-ShankService part / kit
R-20R2284C15/C18/C27/C32 ACERT Trim file (12-digit serial)Service part / kit
R-20R2285C15/C18/C27/C32 ACERT Trim file (12-digit serial)Service part / kit
RSC18ERing Set - PistonService part / kit
RSC18E1Ring Set - PistonService part / kit
M-3687817PistonPiston
138-6744Water pump repair kitPump
161-4113Oil pumpPump
336-2213Water pumpPump
352-0211Water pumpPump
384-8611Lift/transfer pumpPump
384-8612Lift/transfer pumpPump
M-2463130Shaft – Water PumpPump
M-2672839Water pump repair kitPump
M-3848611Pump - TransferPump
142-5867Front sealSeal
142-5868Rear sealSeal
M-2454630Sensor Assembly - SpeedSensor
247-7133ThermostatThermostat
248-5513ThermostatThermostat
420-5855Water Pump Seal Installer (Dimensions: 47 x 45 mm, Weight: .463 kg)Water pump seal installer
PA140VSWinch Model PA140VSWinch

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Also used in

12
  • Atlas Copco DM45 — Drilling Equipment
  • Caterpillar 651 — Tractor
  • Caterpillar 657 — Tractor
  • Caterpillar 745 — Dump Truck Articulated
  • Caterpillar 745C — Dump Truck Articulated
  • Caterpillar 988K — Loader Wheeled
  • Caterpillar PM820 — Planer
  • Caterpillar PM822 — Planer
  • Caterpillar RM600 — Road Equipment
  • New Holland FR9080 — Harvester
  • Sisu C600 — Truck
  • Sisu E18 — Truck

Other equipment known to use this engine, via filter-application cross-reference — useful for sourcing parts even when your exact machine isn't listed elsewhere on this page.

Common questions

What is the displacement of the Caterpillar C18-C?

The Caterpillar C18-C has a displacement of 18.0 liters.

Which generators use the Caterpillar C18-C engine?

The Caterpillar C18-C powers 1 generator set(s), including Northern Lights M843JK.

What is a common problem with the Caterpillar C18-C engine?

A commonly reported issue on generators using the Caterpillar C18-C is: Engine Hard to Start or Will Not Start. Cause: Improper starting procedure. Fix: See starting section of this manual. Take special note of Bypass Switch operation..