Quote:
Originally Posted by theresabusinouryard
2000 international 7.3 Allison
ISSUE: All of a sudden after we filled up a pilot truck stop we are now getting blue smoke upon accelerating and when under load. emits blue smoke for approx 20 seconds then goes away. and only when engine is colder. no loss of coolant noticed - started out of the nowhere when we got to colder weather. (and right after we filled up) Overall feels sluggish (kind of sputtering slightly) when it’s releasing the blue smoke.
Can anyone help with what might be the problem?
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Forgive the length of this post, lots of info and suggestions here.
Blue smoke indicates oil being burned. There is a remote chance your fuel was contaminated with oil, but piston / ring / turbo seal issues are much more likely.
To simplify - what different colors of smoke mean with a diesel --
Blue smoke - oil
Black smoke - overfueling / injection problem
Whitish / grey smoke - underfueling / injection problem
White smoke - coolant entering cylinders
With any of these, do not drive or operate -- liquid in a diesel's cylinders prior to the set injection timing of fuel can destroy the engine almost immediately, fueling problems can lead to bigger problems fairly quickly, and oil consumption can indicate internal mechanical issues, or a warning of a runaway condition brewing.
Piston / ring / cylinder wall issues usually cause more constant smoke. It is, however, quite common for weak / worn turbocharger seals to push oil into the intake, causing smoke.
I would get a professional diagnosis before replacing the turbo, as these can run as much as $1000, but if it does turn out to be turbo oil seals, replace / rebuild the turbo ASAP. If the seals go completely and start really pushing oil non-stop, the engine will run away (accelerate non-stop) until it suffers serious internal damage, either from excessive RPM or from running out of oil, whichever gets it first. This diesel dynomometer video shows the result of a seriously extreme case of runaway from 1:50 on. This idiot really should have known it was going to runaway from the excessive smoke. It appears it was already blowing blue smoke rolling onto the dynomometer.
You can see the brakes glowing yellow / orange / red from the driver trying to hold the engine back, but a 500-1000 hp runaway diesel won't be stopped in this manner. On lower horsepower engines, it is possible to engage the transmission with the brakes set, but I do not recommend this method, as it can cause serious transmission or driveline damage.
To stop a runaway, killing combustion or choking air off to the engine is vital -- and the quicker the better -- though I would caution that if you cannot stop it within 30 seconds to a minute, get away and let it blow, because a diesel grenading can cause serious injury to anyone near it. I have seen some shoot fire extinguishers into the intake or turbocharger to hamper the combustion process, but blocking off airflow / hampering combustion is key. I've seen one fellow throw a phone book into the turbo to stop one. Destroyed the turbo but saved the engine.
I feel the best method of stopping a runaway is to create a vent in the intake snorkel between the filter and turbo that can be opened and closed on demand, but cannot open by itself in normal driving. This provides a quick and easy way to shoot a fire extinguisher or some other combustion-killer (do NOT use water or any other liquid) straight into the intake. Alternately, something similar to an electrically-controlled exhaust cutout could be integrated into the intake snorkel -- acting as a damper to limit / stop airflow in an emergency.
About the fuel contamination thought --
Old 'dirty' highway diesel was essentially fuel oil, which is why some diesels blew black smoke no matter how they were set up. It is still around, just no longer legal for highway engine use -- strictly for non-highway use such as refrigerated trailers, construction equipment, locomotives, etc. Occasionally, an absent-minded fuel delivery truck driver has put the wrong grade of diesel fuel in a tank, but this would cause black smoke, not blue.
A note here, non-highway diesel makes better power than ULSD, but it WILL damage emission-equipped diesel after-treatment systems, and will get you a huge fine if you are caught running it in any highway application today. It is dyed to ease in detection, which is a simple dipping of a stick in the tank to see if the stick shows dye in the fuel (taxable use). Kerosene or jet fuel is also usable in older non-emission equipped diesels. Makes better power, but still no longer legal for highway engine use due to emissions, and double illegal for highway use due to lack of taxation dye.
But as I said, it sounds like you have worn oil seals in the turbocharger pushing oil into the engine, which will essentially make the engine surge independently of the injection system control (outside fuel source, essentially). If that is the case, fix it now or you will wish you had.
One other possibility -- if your automatic transmission is equipped with some type of modulator that can potentially push transmission fluid into the intake, this will be the same thing as blown turbo seals -- but I believe will generally be more consistent, as with ring / piston / cylinder wall issues.
is that Chet?
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