Author Topic: Oil consumption problem  (Read 11843 times)

Onyx Dragon

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Re: Oil consumption problem
« Reply #25 on: September 07, 2014, 12:48:48 PM »
What oil, what OCI, and what climate/driving conditions?  Very important things because ALL engines consume some oil between OCI's.  That's just a plain fact, no such thing as an engine that doesn't consume oil.  NOACK volatility alone will cause a volume decrease.  What ever the factory size is, drilling out to 7/64ths (that's ~0.11" dia. by the way) is not fixing anything to do with a pressure differential.  Transients from the TB vastly outweigh that kind of difference with the PCV.  The stock air filter vs. the K&N filter is also a bogus "fix".  With today's thin oils, 1 qt over a 5,000 mile OCI is not an issue, especially with severe drive cycles and/or temperature extremes.

Synthetic oil, using the weight that the manufacturer calls for.  It also doesn't seem to matter what the weather or driving conditions is, a very large majority of the LY7s tend to go through a lot of oil.   While you're right, every car loses some oil, it's the amount that is being lost that is in question.  My GPs used some oil, but barely any.  Same with my Jeeps.  Some of these engines are using a quart in 1000 miles.  I don't think my mom's is that bad, it's only using 1 quart in 1000 miles, but I am not sure that she is keeping track after dropping 1 quart in it.  My sister currently has it and I put a quart in before she took it.  She says it's still in the full range and it's been 2 weeks.  Not sure of the miles.

Delta

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Re: Oil consumption problem
« Reply #26 on: September 07, 2014, 03:07:19 PM »
For grins and giggles you might try just a cheap dino oil and see what happens. I know on our 3.4 it would eat through a synthetic 1 qt 3,000 miles(IIRC), but I went with a Heavy Duty Syn blend* and consumption is nil every 3,000 miles. Totally different engine and design I know, so don't flame me, but it never hurts to try something easy...




* I did bump up the viscosity to a 10w30, but mainly because HDEO's are not available in a 5w30 easily. With our warm winter climate it's easier to get around that, not too sure on VA winters...
« Last Edit: September 07, 2014, 03:10:16 PM by Delta »
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Onyx Dragon

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Re: Oil consumption problem
« Reply #27 on: September 10, 2014, 01:25:05 AM »
For grins and giggles you might try just a cheap dino oil and see what happens. I know on our 3.4 it would eat through a synthetic 1 qt 3,000 miles(IIRC), but I went with a Heavy Duty Syn blend* and consumption is nil every 3,000 miles. Totally different engine and design I know, so don't flame me, but it never hurts to try something easy...




* I did bump up the viscosity to a 10w30, but mainly because HDEO's are not available in a 5w30 easily. With our warm winter climate it's easier to get around that, not too sure on VA winters...

NoVA winters are usually steady mid 40's and lower.  Quite often at the freezing point, especially at night.  The last couple winters have had some really cold days and snow...which means that when it snows the car isn't starting anyway...If this is working, I'd love to know why.  Like James said, it's not much of a difference, so unless it's some weird pattern that is disrupted just enough, it doesn't make a lot of sense.

Delta

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Re: Oil consumption problem
« Reply #28 on: September 10, 2014, 04:30:10 PM »
NoVA winters are usually steady mid 40's and lower.  Quite often at the freezing point, especially at night.  The last couple winters have had some really cold days and snow...which means that when it snows the car isn't starting anyway...If this is working, I'd love to know why.  Like James said, it's not much of a difference, so unless it's some weird pattern that is disrupted just enough, it doesn't make a lot of sense.

Not too sure myself, but the HDEO( Rotella T5) I run is a thick 10w30 as far as I know. But nothing else has changed in the mix besides what oil I used... Consumption went to nothing in the first regular OCI. I'll know more after this one since there's going to be a 2k mi road trip involved.

Edit: On second thought the firsr OCI I did the oil did get cruddy fast, so maybe the high detergents freed up some stick oil rings...
« Last Edit: September 10, 2014, 04:33:12 PM by Delta »
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MiniVanMan

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Re: Oil consumption problem
« Reply #29 on: September 10, 2014, 06:33:33 PM »
Thicker oil isn't really going to do MUCH if the rings are shot... but what it might do is resist getting past the rings a bit more when the engine and oil are both cold.

Once the engine heats up, the rings will expand a bit and it's probably not burning oil by this point. When the engine is cold, however, and the metal shrinks, that's probably when the oil is getting into the combustion chamber - during first starts until shit gets hot. But once oil is hot, 5W30 and 10W30 are pretty much the same consistency. So again the warm up period is likely when the oil is getting burned, and thicker oil may combat this a bit. Just don't expect a miracle. Not going to hurt anything to try.

Onyx Dragon

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Re: Oil consumption problem
« Reply #30 on: September 11, 2014, 10:25:20 AM »
Thicker oil isn't really going to do MUCH if the rings are shot... but what it might do is resist getting past the rings a bit more when the engine and oil are both cold.

Once the engine heats up, the rings will expand a bit and it's probably not burning oil by this point. When the engine is cold, however, and the metal shrinks, that's probably when the oil is getting into the combustion chamber - during first starts until shit gets hot. But once oil is hot, 5W30 and 10W30 are pretty much the same consistency. So again the warm up period is likely when the oil is getting burned, and thicker oil may combat this a bit. Just don't expect a miracle. Not going to hurt anything to try.

I don't think it's shot rings, honestly.  If it is shot rings, then a very large majority, and by majority I mean most, of the 3.6s on cadillac forums have shot rings.  It's a design flaw somewhere in the engine for sure.  It's possible they were just crappy rings in general.

MiniVanMan

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Re: Oil consumption problem
« Reply #31 on: September 11, 2014, 11:20:05 AM »
I'm not saying anything for sure, but I work next to a 20 tear tech who came from a caddy dealership and he says he's put pistons in many of them. Take that for what it's worth, just offering it up for your consideration.

James

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Re: Oil consumption problem
« Reply #32 on: September 12, 2014, 06:45:51 PM »
Synthetic oil, using the weight that the manufacturer calls for.  It also doesn't seem to matter what the weather or driving conditions is, a very large majority of the LY7s tend to go through a lot of oil.   While you're right, every car loses some oil, it's the amount that is being lost that is in question.  My GPs used some oil, but barely any.  Same with my Jeeps.  Some of these engines are using a quart in 1000 miles.  I don't think my mom's is that bad, it's only using 1 quart in 1000 miles, but I am not sure that she is keeping track after dropping 1 quart in it.  My sister currently has it and I put a quart in before she took it.  She says it's still in the full range and it's been 2 weeks.  Not sure of the miles.

So a 5W-30?  Which brand synthetic?  Is it being checked when the engine is dead cold?  My Ranger will hold almost half a quart from the pan if I check it right after driving.  The PCV system would be saturated if that much was actually being consumed.  I also found mention of checking the orifice holes in the valve cover itself, something that looks like you'd need some pipe cleaners for.
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Onyx Dragon

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Re: Oil consumption problem
« Reply #33 on: September 12, 2014, 10:20:03 PM »
So a 5W-30?  Which brand synthetic?  Is it being checked when the engine is dead cold?  My Ranger will hold almost half a quart from the pan if I check it right after driving.  The PCV system would be saturated if that much was actually being consumed.  I also found mention of checking the orifice holes in the valve cover itself, something that looks like you'd need some pipe cleaners for.

Yeah, 5W30 Mobile 1 high mileage (it's around 88k, but mileage doesn't seem to have any affect on less or more consumption with these engines).  Engine is cold.  The "low engine oil" warning came on one time when she didn't check it as well.  Hopefully there wasn't engine damage from it.  She should be getting it back from my sister soon as we have the Grand Cherokee back in proper working order now.  My sister has said the oil isn't low, so we'll see how that goes.  Maybe it's a particular driving condition.  My mom does almost entirely 2 mile drives to the commuter lot and back home.  She has chiropractor appointments every now and then, but for the most part she puts few miles on it, and usually the car is just getting warmed up when she gets to the lot.  I'll have to see if we can swap for a week and see if it's different seeing as how I drive 40 miles round trip to work.

Delta

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Re: Oil consumption problem
« Reply #34 on: September 13, 2014, 07:22:24 AM »
I think you have partly your answer Onyx. Our Expedition is used the same way with short trips up town barely getting it warm. I once had to add almost a quart in less than 700mi. Drove it to work one couple weeks on a longer drive and didn't have to add anything in the same amount of time. Now as far as the 3.6 consuming oil, it might just be something you have to live with till she gets another vehicle.
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James

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Re: Oil consumption problem
« Reply #35 on: September 13, 2014, 11:48:46 AM »
Yeah, 5W30 Mobile 1 high mileage (it's around 88k, but mileage doesn't seem to have any affect on less or more consumption with these engines).

Yeah, those oils usually do little with healthy engines and because you used an oil that uses extra seal swelling agents you are pretty much stuck using that type of oil.  My Ranger has 188k on it and it still gets Pennzoil Platinum 5W-30 or M1 0W-30, I stay away from "High Mileage".  That type of driving is definitely severe service, oil consumption is going to be an issue because the ratio of engine running time vs miles is pretty lopsided.
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Onyx Dragon

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Re: Oil consumption problem
« Reply #36 on: September 13, 2014, 02:44:55 PM »
Yeah, those oils usually do little with healthy engines and because you used an oil that uses extra seal swelling agents you are pretty much stuck using that type of oil.  My Ranger has 188k on it and it still gets Pennzoil Platinum 5W-30 or M1 0W-30, I stay away from "High Mileage".  That type of driving is definitely severe service, oil consumption is going to be an issue because the ratio of engine running time vs miles is pretty lopsided.

I switched to it because of the consumption (the oil that is).  Hell, her 94 Sundance and the 03 Grand Cherokee barely used oil on the same driving.  This engine just confuses the crap out of me with this.  Went to Indianapolis and back, 2 quarts used.  The more I think about it, maybe Nick's buddy is right about the rings.

m5

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Re: Oil consumption problem
« Reply #37 on: October 09, 2014, 12:03:19 AM »
What oil, what OCI, and what climate/driving conditions?  Very important things because ALL engines consume some oil between OCI's.  That's just a plain fact, no such thing as an engine that doesn't consume oil.  NOACK volatility alone will cause a volume decrease.  What ever the factory size is, drilling out to 7/64ths (that's ~0.11" dia. by the way) is not fixing anything to do with a pressure differential.  Transients from the TB vastly outweigh that kind of difference with the PCV.  The stock air filter vs. the K&N filter is also a bogus "fix".  With today's thin oils, 1 qt over a 5,000 mile OCI is not an issue, especially with severe drive cycles and/or temperature extremes.

Agree my m5 consumes about a liter of oil per cycle. The manufacturer acknowledges this and recommends that you have at least a liter on hand at all times. The porsche consumes it even faster but that is due to oil pooling in the cylinder banks...cost of doing business with a flat six. I wouldn't stress too much about it unless it becomes unmanageable.

MiniVanMan

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Re: Oil consumption problem
« Reply #38 on: October 09, 2014, 07:19:52 AM »
I switched to it because of the consumption (the oil that is).  Hell, her 94 Sundance and the 03 Grand Cherokee barely used oil on the same driving.  This engine just confuses the crap out of me with this.  Went to Indianapolis and back, 2 quarts used.  The more I think about it, maybe Nick's buddy is right about the rings.

As always, can't say for 100% certainty, but the dude is a six-figure earning world class technician so I tend to trust his hunches. That's one of the best performing motors GM has made... But also one of the least reliable. The current generation of them seems to have all the bugs worked out, but only time will tell.