3306C DIESEL TRUCK ENGINE Caterpillar


Excessive White Or Blue Exhaust Smoke

Usage:

White Smoke

Possible Causes/Corrections

Cold Outside Temperatures

When the air outside is cold, the cylinder temperature is cooler. Not all the fuel will burn in the cylinders. The fuel which does not burn comes out the exhaust as white smoke. White smoke is normal in cold temperatures until the engine operates long enough to become warm. There will be less white smoke if No. 1 diesel fuel is used.

Intake Manifold Heater Not Working

If dash light goes out before 60 seconds or is blinking refer to Troubleshooting in Special Instruction, SEHS9773, Installing the 1047618 Intake Manifold Heater.

Long Idle Periods

When an engine runs at idle speed for a long period of time, the cylinders cool and all of the fuel does not burn. Do not idle an engine for a long period of time. Stop an engine when it is not in use. If long idle periods are necessary, use No. 1 diesel fuel.

Engine Operating Temperature Too Low

This can cause white smoke on startup. If the smoke is slow to clear from the exhaust, check and make a replacement of the thermostat if needed.

Low Quality Fuel

Test the engine using fuel according to recommendations by Caterpillar Inc. For more information refer to SEBD0717, Diesel Fuels And Your Engine.

Air In Fuel System

With air in the fuel system, the engine will normally be difficult to start, run rough, and release a large amount of white smoke. If the engine will not start, loosen a fuel injection line nut at the through the head adapter and crank the engine until fuel comes out. Tighten the fuel line nut. Start the engine. If the engine still does not run smooth or releases a large amount of white smoke, loosen the fuel line nuts one at a time at the through head adapters until the fuel that comes out is free of air. Tighten the fuel line nuts. If the air cannot be removed in this way, put 35 kPa (5 psi) of air pressure to the fuel tank.


NOTICE

Do not use more than 55 kPa (8 psi) of air pressure in the fuel tank or damage to the tank may result.


Check for leakage at the connections between the fuel tank and the fuel transfer pump. If leaks are found, tighten the connections or replace the lines. If there are no visual leaks, remove the fuel supply line from the tank and connect it to an outside fuel supply. If this corrects the problem, the suction line (standpipe) inside the fuel tank has a leak.

Fuel Injection Timing Not Correct

Check and make necessary adjustments as in Testing and Adjusting Section of this Service Manual.

Valve Adjustment Not Correct

Check and make necessary adjustments as in Testing and Adjusting Section of this Service Manual. Intake valve lash is 0.38 mm (.015 in) and exhaust valve lash is 0.64 mm (.025 in).

Defective Fuel Nozzle(s)

Defective fuel nozzles will normally cause the engine to "misfire" and run rough, but can cause too much smoke with the engine still running smooth. Remove the fuel nozzles and test as in Testing and Adjusting Section of this Service Manual.

Misfiring Cylinder(s)

See "Misfiring And Running Rough".

Coolant Leakage Into Combustion Chamber

Coolant in the combustion chamber can cause white smoke. A cracked cylinder head or liner, also a defective cylinder head gasket are possible causes for this condition.

Low Compression

Worn piston rings and cylinder liners lower compression pressures, this can cause white exhaust smoke.

Blue Smoke

Possible Causes/Corrections

Engine Oil Level Too High

Do not put too much oil in the crankcase. If the oil level in the crankcase goes up as the engine is used, check for fuel in the crankcase. See "Fuel In Crankcase Oil".

Worn Valve Guides

See the Specifications Section of this Service Manual for the maximum permissible wear of the valve guides.

Worn Piston Rings And/Or Cylinder Walls

Worn piston rings and/or cylinder walls can be the cause of blue smoke and can cause a loss of compression. Make a visual inspection of the cylinder walls and piston rings. If necessary, measure the cylinder walls and piston rings. For the cylinder and piston ring specifications, see the Specifications Section of this Service Manual.

NOTE: High wear at low mileage is normally caused by dirt coming into the engine with the inlet air.

Wear Or Damage To Pistons

Check the piston ring grooves for wear. This engine has piston grooves and rings of the Keystone (taper) design. A 1U6431 Keystone Piston Ring Groove Gauge is available to check the top two ring grooves in the piston. For instruction on use of the gauge, see the subject, "Piston Rings" in the Testing And Adjusting Section of this Service Manual. Pistons which have worn grooves and pistons with damage or defects can cause blue smoke and too much oil consumption. Make sure the oil return holes under the oil ring are open.

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