Regen After A Turbo Failure

[mwilson]

Just wanted to share,



Don't forget this picture below if you have had a turbo failure and have not thought about the oil laying in the exhaust when you put the truck outside and set it for a manual regen... .

It was pretty scary for a couple of minutes, didn't dare to shut it off for fear the truck would burn.

Whole exhaust system was bright red, almost translucent.



Good way to lose a garage or something.



Don't park close to anything flammable. . !!!!!

 

[KLauber]

Is that a stack on fire?

 

[HBarlow]

I bet that little incident was a bit scary for the mechanic who did the work and others with responsibility around your dealership.

What caused it? Did the turbo failure result in engine lube dumped in the exhaust?

 

[mwilson]

Yes, that is the exhaust stack on a Freightliner. Picture is fuzzy as it was from a camera phone. Exhaust stack acting as a torch tip...



Harvey, that is exactly what happened. We are always concerned and very careful to insure the intake system, air to air, etc. are cleaned after a turbo failure but oil left in the exhaust was never an issue until this little lesson occured.



Looked just like a blowtorch, took 15 minutes or so before it all burned out and completely calmed down. Knocked it back to idle once, they say it sounded like a propane torch when you shut it off quickly.



I know that a lot of you guys work on trucks and figured this would give a heads up as to what can happen with a hot DPF in regen if there is any oil in the exhaust.



Mike.

 

[Wingate]

I did that on a 1500 hp. generator engine on a drilling rig one night... . 15W40 makes for a pretty glow at 3-4am

 

[HBarlow]

Mike,

Your description of the burn off sounds like as much as a gallon or two of motor oil drained down the exhaust pipe and settled in the diesel particulate filter then when the dpf heated up it cooked off the oil for fifteen minutes.

Didn't the mechanic wonder where that much oil went when he added make up oil to the crankcase?

There are probably factors here that I don't know about.

 

[mwilson]

Harvey,

It is typical for a gallon or two of oil to disappear either into the intake, exhaust or sometimes both directions in the event of a turbo failure depending on the amount of time that passed before the driver realized what has happened and shuts it down. Sometimes they limp the truck in, other times a tow is needed.



We have had a couple incidents over the years where excess oil due to a turbo failure in the charge air cooler or intake plumbing has resulted in a runaway engine so we watch very closely for that, sometimes the customer will change his own turbo and neglect to mention that he never dealt with the mess in the charge air cooler. Brings it in as the truck still won't run for whatever reason, we repair it, fire it up on all cylinders after the repair and it takes off like the space shuttle. That is always interesting... ...



With that being said any oil left the exhaust system up until the DPF's has never really been a problem, the exhaust system will slowly burn off the oil in the pipes, etc. with no issue.



In the case of the DPF equipped trucks a turbo failure sets several codes in the ECM, including DPF codes because the mixture becomes all wrong, etc.

So we have to put the truck into manual regen after changing the turbo to finish clearing the codes.

That requires the engine to be at or very near governed speed and to heat the DPF to 1400 degrees or so to clean itself.



There is really no way to tell how much oil is lurking in the DPF, we may have to include from here on in a visual inspection of the internals before doing the manual regen.

And remember on a Class 8 engine oil dipstick the amount of oil referenced from the full mark to the add mark is 1 gallon, not 1 quart.

No way for the tech to tell if the truck pushed that gallon into the exhaust or in some cases drivers leave them at the add mark to reduce crankshaft windage.



We are still discussing it here as we have changed many turbos on DPF equipped units but for some reason this one turned into a flamethrower.



Thank God we always put them outdoors before doing a manual regen!!!!



Mike.

 

[Bill Stockard]

I remember years ago, occasionally a driver would ask how to make flames come out the exhaust stacks at night... now they know how.



Better than mothballs in the fuel tank. :-laf



Bill

 

[Wingate]

With that being said any oil left the exhaust system up until the DPF's has never really been a problem, the exhaust system will slowly burn off the oil in the pipes, etc. with no issue.



Mike.

ITs only an issue when you don't have the time to let it burn off at lower temps...

Much like your situation, many times when we make a reapir, the customer is wanting to immediately put the engine back online... Typically, we could just put one at rated speed at no load and burn off any oil/fuel from the repair... . just some smoke... but when you have a drilling rig on down-time, you sometimes dont get that luxury. .

We let it run about 5 minutes to check for leaks. . etc... and drop the hammer on them, rated speed and 80%+ load. The gallons of oil,fuel, or antifreeze in the muffler really puts off a nice glow when u hit it with 1200 degree exhaust temps. .