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Caterpillar 3204 Engine

The Caterpillar 3204 is a heavy-duty, inline 4-cylinder diesel engine belonging to the legacy 3200-series family. Primarily utilized in mid-sized Cat earthmoving machinery - such as the 931 and 943 track loaders, D3 dozers, and various industrial applications - it is engineered as a compact, mechanical workhorse. The engine features a robust cast-iron block and cylinder head, available in both naturally aspirated (NA) and turbocharged configurations.

Fuel Injection Type: Uses direct injection (DI) via pencil-type fuel injectors or capsule nozzles fed by external steel high-pressure fuel lines. Fuel Injection Pump: Mechanical, sleeve-metered injection pump or high-pressure scroll fuel system, depending on the serial number prefix. Fuel Transfer: A mechanical fuel transfer pump maintains a low-pressure supply of 30 to 40 psi to the injection pump gallery. Governor: Mechanical flyweight governor integrated directly onto the rear of the fuel injection pump housing.

Lubrication System: Full-pressure, wet-sump system driven by a gear-type oil pump. Oil Filtration: Features a spin-on, full-flow bypass oil filter paired with an integrated plate-type oil cooler element. Service Practice: Mechanics must monitor oil pressure closely during cold starts. Shavings in the oil filter or a severe drop in hot idle pressure indicate primary main or connecting rod bearing degradation.

Cooling System: Liquid-cooled, closed-loop circuit utilizing a centrifugal, gear-driven water pump. Flow Circuit: Coolant is forced through the engine block jacket, ascending into the cylinder head, and regulated by a single kapsel-type thermostat (regulator) housed at the front upper water outlet.

General Technical Data

Engine Specifications

Engine Model ............... Caterpillar 3204
Engine Type ............... 4-cycle inline 4-cylinder direct injection liquid-cooled diesel
Number of Cylinders ............... 4
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 4.25 (108.0)
Engine Stroke, in (mm) ............... 5.00 (127.0)
Displacement, cu.in (L) ............... 269 (4.4)
Rated Engine Power (Naturally Aspirated), hp (kW) ............... 60-75 (45-56)
Rated Engine Power (Common Applications), hp (kW) ............... 60-95 (45-70)
Rated Engine Power (Turbocharged), hp (kW) ............... 110-120 (80-90)
Rated Engine Speed, rpm ............... 2100-2800
Idle speed ............... 650-750 rpm
Aspiration Type ............... Naturally Aspirated or Turbocharged
Operating Speed ............... 2500 rpm
Compression Ratio ............... 16.5:1
Firing Order ............... 1-3-4-2
Crankshaft Type ............... Forged steel
Piston Type ............... Cast-aluminum alloy
Con Rod Type ............... Forged steel
Cylinder Block Type ............... Cast iron
Cylinder Head Type ............... Cast iron
Lubrication System ............... Full-pressure
Oil Pump Type ............... Gear-driven
Oil Filter Type ............... Full-flow, spin-on
Cooling System ............... Liquid-cooled
Water Pump Type ............... Belt-driven, centrifugal
Air Cleaner Type ............... Dry dual-stage
Starting System ............... Electric Starter
Electrical System ............... 12V or 24V
Alternator Rating, Amps ............... 45-65

Fuel System

Fuel System ............... Direct injection
Injection Pump Type ............... Distributor, rotary
Fuel System Control ............... Mechanical
Governor Type ............... Mechanical
Fuel Injector Type ............... Multi-hole
Fuel Type ............... Diesel Fuel

Dimensions and Weight

Overall Length, in (mm) ............... 35.4 (900)
Overall Width, in (mm) ............... 25.6 (650)
Overall Height, in (mm) ............... 33.5 (850)
Dry Weight, lbs (kg) ............... 1100 (500)

Maintenance Data

Service Information

Thermostat begins opening ............... 82C (180F)
Thermostat fully open ............... 91C (195F)
Cooling system pressure ............... 50-90 kPa (7-13 psi)
Operating oil pressure ............... 200-410 kPa (30-60 psi)
Idle oil pressure ............... 70-100 kPa (10-15 psi)
Intake Valve Clearance, in (mm) ............... 0.015 (0.38)
Exhaust Valve Clearance, in (mm) ............... 0.025 (0.64)

Engine Oil and Coolant

Engine Oil Type .................. SAE 10W-30, 15W-40
API Service Classifications ......................... CD or CE
Engine Oil Capacity, qts (L) .................. 10.0-13.6 (9.5-13.0)
Coolant Capacity, qts (L) ............... 13.6-21.0 (13.0-20.0)

Service Intervals

Change oil and filter ............... Every 250 hours
Replace fuel filters ............... Every 250 hours
Inspect air filter ............... Every 50 hours
Change coolant ............... Every 2 years
Valve-lash adjustment ............... Every 1000 hours
Injector inspection ............... Every 1000-1500 hours
Compression test ............... Every 2000 hours
Drain water separator ............... As required
Belt inspection ............... As required

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ................ 4.2500-4.2520 (107.950-108.001)
Crankshaft Journal Outside Diameter, in (mm) ................ 3.4990-3.5000 (88.875-88.900)
Crank Pin Outside Diameter, in (mm) ................ 2.9990-3.0000 (76.175-76.200)
Crankshaft End Play, in (mm) ................ 0.0030-0.0100 (0.076-0.254)
Intake Valve Stem Outside Diameter, in (mm) ................ 0.3715-0.3721 (9.436-9.451)
Exhaust Valve Stem Outside Diameter, in (mm) ................ 0.3710-0.3716 (9.423-9.439)
Intake Valve Guide Inside Diameter (Installed), in (mm) ................ 0.3741-0.3751 (9.502-9.528)
Exhaust Valve Guide Inside Diameter (Installed), in (mm) ................ 0.3741-0.3751 (9.502-9.528)
Intake Valve Stem to Guide Clearance, in (mm) ................ 0.0020-0.0036 (0.051-0.091)
Exhaust Valve Stem to Guide Clearance, in (mm) ................ 0.0025-0.0041 (0.064-0.104)
Intake Valve Spring Free Length, in (mm) ................ 2.464 (62.59)
Exhaust Valve Spring Free Length, in (mm) ................ 2.464 (62.59)
Intake Cam Height, in (mm) ................ 1.720-1.730 (43.688-43.942)
Exhaust Cam Height, in (mm) ................ 1.720-1.730 (43.688-43.942)
Piston Pin Outside Diameter, in (mm) ................ 1.5003-1.5006 (38.108-38.115)
Piston Pin to Piston Bore Clearance, in (mm) ................ 0.0003-0.0009 (0.008-0.023)
Top Ring Side Clearance, in (mm) ................ 0.0033-0.0047 (0.084-0.119)
Second Ring Side Clearance, in (mm) ................ 0.0028-0.0041 (0.071-0.104)
Oil Ring Side Clearance, in (mm) ................ 0.0015-0.0035 (0.038-0.089)
Top Ring End Gap, in (mm) ................ 0.0140-0.0220 (0.356-0.559)
Second Ring End Gap, in (mm) ................ 0.0100-0.0180 (0.254-0.457)
Oil Ring End Gap, in (mm) ................ 0.0100-0.0200 (0.254-0.508)

Tightening Torque Specs

Cylinder head bolts ............... 100-200 Nm (74-148 lb-ft)
Main bearing cap bolts ............... 140 Nm (103 lb-ft)
Connecting rod bolts ............... 100 Nm (74 lb-ft)
Flywheel housing-to-block bolts ............... 75 Nm (55 lb-ft)
Flywheel-to-crankshaft bolts ............... 115 Nm (85 lb-ft)
Oil pan bolts ............... 27 Nm (20 lb-ft)
Injector clamp bolt ............... 35 Nm (26 lb-ft)
Fuel injection pump mounting bolts ............... 24 Nm (18 lb-ft)

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• Caterpillar Engines Specs
  
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• Cat 3304B Specs
  
• Cat 3306 DITA Specs
  

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