Author Topic: 6.2 Oil consumption  (Read 6531 times)

Offline K20Detroit

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6.2 Oil consumption
« on: January 22, 2016, 11:59:35 AM »
During the summer months, I ran 15w40 Rotella T and had little to no oil consumption (drove 6k miles, never had to add.) It never smoked or anything.
Now that winter has hit, I have had a bit of oil consumption. Nothing I consider excessive, but it does concern me that it only happens in the cold when my other vehicle does it whether it is cold or hot out.
When winter first hit, I stayed with 15w40 due to the manual claiming it was set for the mild winters we get where I live. When I noticed the consumption, I started adding 10w30 Rotella T. The truck starts much easier, though I will likely be adding 5w40 Rotella instead due to recommendations on here.
On startups at 20F; there is sometimes blue smoke for the first second. After the first second, it clears up and doesn't smoke at all. Sometimes on heavy throttle, some blue gets mixed in with the light black smoke. Not often.

Notes;
Air filter is new, glow plugs are fairly new.
Bosch oil filter
Possibly needs t-stat (takes long time to warm up, never goes over 120 at 30F.)

Offline LTZ C20

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Re: 6.2 Oil consumption
« Reply #1 on: January 22, 2016, 11:19:35 PM »
Valve seals are mostly likely bad, oil is leading the into the cylinders when it's not running and burns off when you first start it, thus the blue smoke. Valve seals are fairly common for an engine that has decent milage on it and is older. My old 350 did the except same thing, except it would smoke enough to make diesels look childish. New valve seals fixed the problem completely. It is possible some leakage can be coming as way of blow by past the piston rings but valve seals are more your culprit due to it happens when you start it. Oil has to drip DOWN past the seals. It's can't drip UP past the piston rings while it's not running. The little blue smoke on acceleration is the same cause, the seals are moving enough or worn enough to allow leakage on heavy throttle. For now, I wouldn't worry about the piston rings being the issue, most likely cause is the valve stem seals.
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Offline K20Detroit

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Re: 6.2 Oil consumption
« Reply #2 on: January 23, 2016, 11:40:27 AM »
The thing that has me wondering is, it only happens in cold temperatures.
We have weeks where one day is 30F, the next is 60F+.
The 30F day, it'll do the light smoking. The next 60F day, no smoking at all.
Is it as simple as the extra heat causing a better seal?

When my '66 Galaxie had the valve seals go bad, it was pretty much a smoke show all the time. What this truck puts out pales in comparison to that, which is why valve seals really didn't cross my mind.

Offline LTZ C20

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Re: 6.2 Oil consumption
« Reply #3 on: January 23, 2016, 02:23:52 PM »
The temperature drop could be enough to cause the seals to shrink up when the engine is completely cold, like sitting over night. 60° isn't all that bad, 30° is below freezing. When my old engine did it, it would have to sit for a long time, like over night or a full day of being at school. Anything less then 6 hours of sitting it never happened. Seals are a wearable item and just as susceptible to temperature variation as a radiator hose.
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Offline bd

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Re: 6.2 Oil consumption
« Reply #4 on: January 23, 2016, 02:26:20 PM »
Here is some cracker barrel discussion and my idle thoughts:
Heat plays a huge role.  Dependent partially on fuel characteristics, combustion can suffer significantly when an engine is cold.  Diesels rely on the heat generated from cylinder pressure for effective combustion rather than an artificial source such as the spark employed in a light fuel engine.  Initially, when a diesel is cold, supplemental heat from the glow plugs improves combustion until cylinder temperatures alone become sufficient to support it.  Lower combustion efficiency at cold startup means that any "normal" amount of oil present in the cylinder won't burn as well either - hence, short-lived blue smoke until cylinder temperatures rise sufficiently.  At the very least, you should verify glow plug health and their proper operation.  You might even consider using a block heater or heated pan blanket if the smoke is really bothersome.  Replace the t-stat; 120° F at operating temperature is too cold.

However, in your first post you stated, "On startups at 20F; there is sometimes blue smoke for the first second. After the first second, it clears up and doesn't smoke at all."  Frankly, that doesn't sound like an issue regarding a diesel powerplant in icy weather.  Nonetheless, there maybe sufficient accumulated hours and normal wear on the engine to pass slightly more oil into the cylinders, manifesting as blue smoke - more so when cold and combustion is less complete.  Collectively, worn valve guides and seals, minor ring wear, cylinder glazing, carbon accumulation in the ring grooves, increased fuel dilution of the oil, etc, are more likely "combined" causes contributing to a minor increase in cylinder oil, especially with moderate to high mileage.

Essentially, aside from the thermostat, it doesn't sound like you have a significant issue to be overly concerned about at this point in time.
« Last Edit: January 24, 2016, 12:43:52 PM by bd »
Rich
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In other words... if people learn by making mistakes, by now I should know just about everything!!!
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Offline LTZ C20

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Re: 6.2 Oil consumption
« Reply #5 on: January 23, 2016, 02:36:32 PM »
And we just got schooled..... haha.
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Offline TGPJr

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Re: 6.2 Oil consumption
« Reply #6 on: January 24, 2016, 12:43:44 AM »
BD pretty well summoned it up.
It's typical Diesel.
Blue smoke on cold start is normal.
You need to change the Thermostat asap.
Cold Cylinder temps cause all sorts of problems.
Tom
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Offline LTZ C20

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Re: 6.2 Oil consumption
« Reply #7 on: January 24, 2016, 12:58:38 AM »
I had assumed that being a diesel owner he knew smoke was normal and he was concerned about an excess blue smoke. I must have been wrong.
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Offline bd

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Re: 6.2 Oil consumption
« Reply #8 on: January 24, 2016, 01:04:11 PM »
LTZ, I think your understanding of the OP's concern is spot on.  For there to occur an unexpected and seemingly sudden change in the "normal" operation of one's vehicle would have most people wondering.  What I am wondering now is whether K20Detroit is settled with the response?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
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Offline LTZ C20

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Re: 6.2 Oil consumption
« Reply #9 on: January 24, 2016, 02:10:18 PM »
Well that makes sense then. Sounds good to me, we will have to wait and see how he responds.
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Offline Irish_Alley

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Re: 6.2 Oil consumption
« Reply #10 on: January 24, 2016, 04:38:56 PM »
im going to add this. idk about the 6.2 that much but my cummins would hardly reach 100° till i blocked off the radiator. first i blocked off 100% but the temps would be about 210° trans temp would be about 70° in 30° weather. i unblocked it a tad now its maybe ½ blocked maybe a little more. but the OT of her now is about 140°

AND she will smoke for about one minute really bad during these cold morning
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Offline K20Detroit

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Re: 6.2 Oil consumption
« Reply #11 on: January 27, 2016, 03:12:21 PM »
Here is some cracker barrel discussion and my idle thoughts:
Heat plays a huge role.  Dependent partially on fuel characteristics, combustion can suffer significantly when an engine is cold.  Diesels rely on the heat generated from cylinder pressure for effective combustion rather than an artificial source such as the spark employed in a light fuel engine.  Initially, when a diesel is cold, supplemental heat from the glow plugs improves combustion until cylinder temperatures alone become sufficient to support it.  Lower combustion efficiency at cold startup means that any "normal" amount of oil present in the cylinder won't burn as well either - hence, short-lived blue smoke until cylinder temperatures rise sufficiently.  At the very least, you should verify glow plug health and their proper operation.  You might even consider using a block heater or heated pan blanket if the smoke is really bothersome.  Replace the t-stat; 120° F at operating temperature is too cold.

However, in your first post you stated, "On startups at 20F; there is sometimes blue smoke for the first second. After the first second, it clears up and doesn't smoke at all."  Frankly, that doesn't sound like an issue regarding a diesel powerplant in icy weather.  Nonetheless, there maybe sufficient accumulated hours and normal wear on the engine to pass slightly more oil into the cylinders, manifesting as blue smoke - more so when cold and combustion is less complete.  Collectively, worn valve guides and seals, minor ring wear, cylinder glazing, carbon accumulation in the ring grooves, increased fuel dilution of the oil, etc, are more likely "combined" causes contributing to a minor increase in cylinder oil, especially with moderate to high mileage.

Essentially, aside from the thermostat, it doesn't sound like you have a significant issue to be overly concerned about at this point in time.
Glow plugs are in good health. Not sure which ones were installed, however shortly before I purchased the truck, they were replaced by a reputable shop.
It sounds like I don't have too much to worry about at the moment, just ordering the t-stat and gasket.

Offline K20Detroit

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Re: 6.2 Oil consumption
« Reply #12 on: January 27, 2016, 03:16:32 PM »
I had assumed that being a diesel owner he knew smoke was normal and he was concerned about an excess blue smoke. I must have been wrong.
I've dealt with 7.3's in the past that didn't smoke like this, this 6.2 is my first diesel that puts off anything other than a small amount of black smoke. However, the 7.3 diesels were 10-15 years newer.

im going to add this. idk about the 6.2 that much but my cummins would hardly reach 100° till i blocked off the radiator. first i blocked off 100% but the temps would be about 210° trans temp would be about 70° in 30° weather. i unblocked it a tad now its maybe ½ blocked maybe a little more. but the OT of her now is about 140°

AND she will smoke for about one minute really bad during these cold morning
I have my radiator blocked off on my brush guard. It helps a little, but still only 120F at anything below freezing. It has to be around 55F for it to reach 160F.
« Last Edit: January 27, 2016, 03:22:01 PM by K20Detroit »