[C320-list] White Smoke from Diesel Exhaust

[Bob Borelli]

My diesel exhaust is emitting white smoke, possibly blue white, about 3 to 4 feet long at operating speed of 2800 rpms.  The smoke remains at the water surface until dissipating.   No smoke at start up or idle at 1000 rpms.  This 1995 Perkins M30 diesel has 1560 hours.

The diesel is not overheating.  I have had the underwater hull cleaned.  Appears to be good raw water overflow from the exhaust.  Various temperature readings around the diesel & exhaust at operating speed of 2800 rpms have remained the same.  No loss of coolant.  Raw water impeller good.  No water in the Racor bowl.  Fuel filters new.   Additives used are Biobor MD & JF.  Fuel  purchased fuel from truck stop.

The no. 1 injector temp (197F) is less then no. 2 & no. 3 (220F).     I don’t know if injectors have been serviced in the 1560 hours.  The tech manual states service after 900 hours.  My plan is to have the injectors removed for testing.

Has anyone had similar white smoke issues from their diesel?  And how resolved?





What creates White Smoke from diesel exhaust?

White Smoke is nearly always water vapor & is quite normal when engine is first started.

However if it persist for more then a few seconds, engine could have problems:



White Smoke indicates Overheating!  Steam! Due to restricted Injection Elbow!  Test by measure the temperature in the ‘Wet’ portion of Exhaust Hose, should be below 200F. insufficient raw water flow.



Overcooling - cylinder head & combustion chamber operate at temperatures too low for proper combustion (my cylinder no.1 lower temp?)



White Smoke represents atomized fuel, very small droplets of fuel that cause a fog.

White Smoke from exhaust indicates diesel fuel not burning correctly - the Injectors.

Fuel is not burning completely.   Replace fuel Injector.

Raw diesel fuel is passing thru combustion chamber into the exhaust stream.

White smoke unburned fuel indicates damaged injectors.



Preheat device - Glow Plugs malfunctioning?



Poor fuel quality (not formulated as no. 2 diesel), add fuel Cetane Booster may temporarily alleviated & identify poor quality fuel as problem.  Contaminated Fuel.  Water in the fuel.



Low pressure to the fuel pump.  Damaged or incorrect fuel pump timing.  Dirty fuel filter.



Poor Atomization of Fuel - Injectors

Injector nozzle stuck open [1].    Injector nozzle seat worn [1].   Injector pressure low [1].

Low fuel grade [4].   Injection timing retarded [4].



Poor Compression:

Low cylinder compression.   Leaking inlet or exhaust valve [3].   Piston rings stuck in grooves [3]

Worn piston rings and cylinders [3].  Piston ring blow by.    Damages rings.



Water in the fuel:

Check Coolant Level

Coolant working its way into cylinders & burning along with the fuel.

Blown Head gasket - cooling water escaping from galleries & entering a combustion chamber.

Water mixed in fuel from cracked head gasket, cylinder head or block.



·          Inspect Valve Seals for signs of leakage.   Poorly adjusted valves or worn valve seats.



·          Cracks in Intake Manifold Gasket

·          Cracks in Head Gasket or Head gasket blown.



·          Cracks in cylinder head

·          Cracks in exhaust manifold.

·          Cracks in engine block.

·          Inspect Piston Rings for signs of leakage.



·          Damaged timing gear