Blue smoke?
Thread Starter
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Elder User
Joined: Oct 2004
Posts: 782
Likes: 1
From: Olympia, WA
Blue smoke?
I've noticed that after a long downhill where I'm compression braking, that when I first get back on it, I get a puff of blue. No starting or running issues whatsoever. Smokes when cold if you let it idle, but if driven, smoke clears quickly. Just blows a little blue now and then when I first romp on it, it's gone before the first shift. I'm thinking maybe the motor is just showing it's age at 230K and valve seals are leaking. Other would be EGT getting so low that maybe incomplete combustion? No noticeable oil consumption though, so unsure if it's fuel or oil. Any thoughts? Not really worried about it, just curious if anyone else has been in this spot and had bigger problems that I should plan for.
Lead Driver
Joined: May 2007
Posts: 8,608
Likes: 13
From: Belair md
probably fuel, i get a lot of smoke while compression braking with the exhaust brake. pretty impressive. and when i get on it afterwards i get a puff as well. i see you have stage 1's. it may just be the excess fuel in the cylinders from them. or possibly a small leak from one?
Postmaster
Joined: Jan 2004
Posts: 3,207
Likes: 0
From: Kearney, Nebr
I agree with c00n on this one. Sounds like excess fuel to me, especially if you are compression braking.
My almost always smokes at startup. It always clears up once you get the egt's around 250.
My almost always smokes at startup. It always clears up once you get the egt's around 250.
Thread Starter
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Elder User
Joined: Oct 2004
Posts: 782
Likes: 1
From: Olympia, WA
It doesn't smoke while compression braking, but immediately afterward, as soon as I get on it to speed back up. EGT easily goes below 300, maybe it's just fuel. Doesn't happen much under normal driving, just after a long downhill, or when I first get on it after putting around slow for a while where EGT is pretty much same as extended idling.
FOREIGN GURU
Joined: Jul 2006
Posts: 7,655
Likes: 7
From: Celaya, Gto. MX
I have this in my book:
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.
so maybe it could be normal.
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.
so maybe it could be normal.
Postmaster
Joined: Jan 2004
Posts: 3,207
Likes: 0
From: Kearney, Nebr
See this is what I don't understand. We turn the pumps up on our tractors and they smoke pretty good at idle. The smoke is clearly blue. Doesn't matter if its cold or a hot engine.
I still say blue smoke is ok on a diesel unless its excessive.. unless you have some serious cc's going through there.
I still say blue smoke is ok on a diesel unless its excessive.. unless you have some serious cc's going through there.
