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Discussion Starter · #1 ·
Truck is a 2006 duramax.

Has a EFI live with very mild tunes (highest is 120), DPF, EGR, Cat's are gone.


The other night I got a "low oil" warning. Today, I added a quart, than another and finally almost 3 quarts later the level was where it should be. According to computer I'm 35% oil life left.

There's still snow up here so I know there's no oil drips. I check the snow for tranny fluid often.

I'm using AMS oil premium diesel oil as specified from their website and a EAO filter from AMS.

I know some trucks burn certain oils more than others, but 3 quarts is insane.

Truck has never over heated. It idles for about 15-20 mins each morning before work due to winter.

I don't think there's smoke coming from my tail pipe, unless I step on it when using 120 horse power. MY wife said she thought she saw some smoke while driving behind me the other day.


What gives?
 

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How many miles or months since last oil change? Did you ever check oil level since last oil change? Ignore the DIC regarding oil life.
 

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1-qt loss @ 3-5k miles is acceptable, varying with use. Nothing on the dip-stic = at least 2 qts low.

How long / many miles since you last checked the level? 65% DIC in miles could very well be 3 qts.
 

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Do you change your own oil?
 

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The DIC is very accurate on oil life, but you still must check the oil level on a periodic basis. As others have asked, how many miles since the last change?
 

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Discussion Starter · #6 ·
I do change my own oil. I am mechanically inclined so its not an error in the process.

I'm about 7,000 km's on this oil.


My LMM never burned more than a 1/4 of a quart between changes.

Why such differences?
 

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Do you notice any smoke on first startup? I know it's been cold but that may indicate valve seals leaking. Turbo seals may be leaking a little burning that way too. Other than that possibly enough blowby to cause the oil to go through the PCV and burn slowly as it enters the engine or just simply burning off the walls of the cylinder if the rings are worn enough. Is the PCV still routed into the drivers side intercooler tube? If so you can inspect the tube for oil residue. It may show if the PCV or turbo is leaking. If you have no sign of oil there, you need to check compression.
 

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Discussion Starter · #8 ·
Do you notice any smoke on first startup? I know it's been cold but that may indicate valve seals leaking. Turbo seals may be leaking a little burning that way too. Other than that possibly enough blowby to cause the oil to go through the PCV and burn slowly as it enters the engine or just simply burning off the walls of the cylinder if the rings are worn enough. Is the PCV still routed into the drivers side intercooler tube? If so you can inspect the tube for oil residue. It may show if the PCV or turbo is leaking. If you have no sign of oil there, you need to check compression.
THanks for the info.

No, it doesn't really smoke when I start it. Even when it's a little cold. Of course when it's -20 it smokes a bit.

It could be the turbo seals maybe. I notice when its on 120 horse it blows some black smoke when I step on it. The same setting on my LMM did not blow black smoke. I was told this could be a leaky turbo. On the turbo piping there is some grease/oil, almost like a small leak is pushing out crude. Could this be? And could it be oil?

Yes the PCV is still routed stock. If there's oil here, what should I check next?

Is there a way to pressure check the turbo system and diagnose leaks?
If there's oil in the intercooler, does this mean the turbo is shot?
 

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Well like I said, 2 things will allow oil to enter the intercooler. One is the turbo seals. The other is the PCV. The easiest way to figure out which of the 2 it is would be to reroute the PCV and clean the intercooler tube. If after another 7000km the intercooler tube is still coated in new oil you can assume the turbo is the culprit. If the intercooler tube is clean but the PCV tube is coated, then you can assume there is slight blowby causing oil to blow out the vent.
 

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Discussion Starter · #10 ·
Well like I said, 2 things will allow oil to enter the intercooler. One is the turbo seals. The other is the PCV. The easiest way to figure out which of the 2 it is would be to reroute the PCV and clean the intercooler tube. If after another 7000km the intercooler tube is still coated in new oil you can assume the turbo is the culprit. If the intercooler tube is clean but the PCV tube is coated, then you can assume there is slight blowby causing oil to blow out the vent.
I heard re routing the PCV isn't good. I know lots of guy's do it though.

If I do the re route and the the PCV tube is coated afterwhile and there's blowby, is this bad?
 

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I heard re routing the PCV isn't good. I know lots of guy's do it though.

If I do the re route and the the PCV tube is coated afterwhile and there's blowby, is this bad?
Rerouting the PCV will not effect your truck in any way. Its routed back into the intake from the factory for the sake of emissions. On the old LB7 like I had, the PCV vented to the atmosphere from the factory. Some people vent the PCV to the atmosphere but install a catch can for any oil that may go out the hose. This would eliminate the negative effects of the reroute.

If the oil is coming from the additional pressure in the crankcase it is, and isn't a problem. While all used diesels tend to have some blow by, yours would be substantial enough to push oil out the motor. That is not good and would lead me to do a compression check to see just how bad it is. On the other hand, it's not bad enough to effect performance by the sounds of it. So maybe all the rings are equally worn, which would not be as bad as one piston with a crack or broken/missing rings.

But all that is neither here nor there if the turbo is the culprit.
 

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Discussion Starter · #12 ·
Rerouting the PCV will not effect your truck in any way. Its routed back into the intake from the factory for the sake of emissions. On the old LB7 like I had, the PCV vented to the atmosphere from the factory. Some people vent the PCV to the atmosphere but install a catch can for any oil that may go out the hose. This would eliminate the negative effects of the reroute.

If the oil is coming from the additional pressure in the crankcase it is, and isn't a problem. While all used diesels tend to have some blow by, yours would be substantial enough to push oil out the motor. That is not good and would lead me to do a compression check to see just how bad it is. On the other hand, it's not bad enough to effect performance by the sounds of it. So maybe all the rings are equally worn, which would not be as bad as one piston with a crack or broken/missing rings.

But all that is neither here nor there if the turbo is the culprit.
Thank you. I'll spend some time with it and give an update when I narrow it down.
 
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