Thanks for tour reply Johnsdiesel can this cause any major damage if left to long.

 

When it is cold out below 30f my truck will have black smoke. If it warm out it will not smoke. It is a dam good truck I love it. 2000 F350 4x4drw 9ft rack body 6speed 4.10 gears.

 

I wouldn't think that oil running through the injectors is a good idea, but I don't think you can cause major damage unless you never fix it. If you have a loose injector because of the o-rings that might cause damage. Fix it soon, but you don't have to stop driving the truck in the meantime.

 

I have heard that unburnt fuel is a lot of why the truck will smoke when you start it. Anybody agree?

 

johnsdiesel, my 03 7.3 will smoke light hazy blue only on cold days,the colder it is the longer it smokes. has been this way since new. the smoke smells like diesel fuel not oil. the truck uses less than a quart to 4000 miles.are you sure its abnormal? anyone else in a cold climate get blue smoke on startup?

 

Yes, visible smoke is unburned fuel. I think the blue smoke some of you are describing is what I and others consider white. I'm not talking white as snow, but not blue. Blue smoke is not caused by unburned fuel alone. When you have black smoke it usually means you are not getting enough air to burn the fuel injected. White smoke usually means the engine is not warm enough to burn all the fuel. Some white smoke is normal on cold starts, but excessive white smoke usually means there is some problem in the glow plug circuit or low compression.

I wouldn't worry about smoke unless it seems excessive. It's also common to use some oil between changes and I would think in extremely cold climates more smoke would be common.

Want to be paranoid? Here's a smoke analysis that gives about every possible cause of smoke from Steve's website. He covers most of the common causes of smoke I mentioned and a lot of other less common causes. At any rate, CONTINUE READING KNOWING THAT YOU WILL NOW BE PARANOID ABOUT ANY SMOKE. STOP HERE IF YOU WANT TO AVOID PARANOIA.

http://pages.prodigy.net/stevebaz/_i...az/index3.html

White smoke:


Caused by unburned fuel passing through the engine. Some white smoke is normal on cold start-ups. Excessive white smoke could be an indication of inoperative glow plugs, loose injectors, low compression from worn rings or bent connecting rods, or coolant leak into the cylinders--head gasket or injector well sleeves.

Black smoke:


Caused by excessive fuel for the amount of air drawn into the cylinders. Some black smoke on hard accelerate or at higher altitudes is normal. Excessive black smoke could result from restricted intake or exhaust, inoperative leaking or weak turbo, intake hose(s) leaks, leaking or worn injectors, fuel return or supply restriction, stuck Exhaust Back Pressure Regulator valve or solenoid. Also PCM inputs such as BARO MAP ICP or EBP sensors.

Blue or blue/white smoke:


Caused by insufficient fuel or oil consumption. Normal when engine is cold or idling for extended periods. Excessive smoke could be caused by air in the fuel, contaminated fuel, loose or plugged injectors, worn or leaking injector o-rings, thermostat stuck open, oil consumption, or plugged crankcase depression regulator valve. Also PCM inputs such as MAP or ICP sensors.

 

I believe this is the crux of this thread.....remember folks, there is a reason diesels are called "oil burners". A cold engine on a cold morning will smoke, and it will invariably have a bluish tint to it. It is the nature of the beast and completely normal.

In my experience pure white smoke is almost always coolant, dropped a valve, blown headgasket, etc., but that normally produces huge billowing clouds of white smoke. A little bit of smoke, whatever the color, is rarely anything to worry about, but should not be ignored either as it can be a sign of things to come.