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  #21  
Old 12-23-2019, 07:47 PM
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The oil is leaking by the rings and is being burned.

Subaru considers one quart burned for every 1,000–1,200 miles to be within “normal specifications.” That means if you follow their recommended changing schedule, which is usually 5,000 miles, you’ll probably need to top of your oil reservoir 4 times or so.

So basically you have to carry a quart of oil around with you. I really don't know why you ever need to do an oil change because it's being changed on a continual basis. Maybe change the filter at 5000 and call it good.
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  #22  
Old 12-23-2019, 09:43 PM
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Originally Posted by tnmike View Post
The oil is leaking by the rings and is being burned.
Or the valve guides or both...
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  #23  
Old 12-24-2019, 12:27 AM
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Thicker oil is really only bad if the car sits for days without it running. The upper part of the engine might be loud for a bit. I doubt going up 5 is going to be noticeable.
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  #24  
Old 12-24-2019, 04:16 AM
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From this site.

QUOTE
"What causes these already prone for oil consumption Subaru engines to start burning the oil? There are 4 to 5 oil drain back holes in the pistons that plug up not allowing the oil to drain through the oil scraper rings. The rings also get stuck in the piston not scraping the oil off the cylinder correctly. These two things cause the excessive oil consumption. "

https://mdhmotors.com/subaru-oil-con...roblem-repair/
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  #25  
Old 12-24-2019, 05:49 AM
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That is interesting info GWIZ. I have owned Subarus for decades. I wonder why this problem never appeared before synthetic oil?
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  #26  
Old 12-24-2019, 12:15 PM
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Originally Posted by tnmike View Post
That is interesting info GWIZ. I have owned Subarus for decades. I wonder why this problem never appeared before synthetic oil?

The new 'in thing' is to have complicated pistons that sacrifice longevity for performance, they don't really have skirts etcetera.

One of the issues with chryslers 4..7 was that the piston did not shed heat to the block enough. This made synthetic mandatory.
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  #27  
Old 12-24-2019, 08:08 PM
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Time for the Bon Ami treatment
Thats what i was thinking.
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  #28  
Old 12-25-2019, 01:33 PM
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Thicker oil is really only bad if the car sits for days without it running. The upper part of the engine might be loud for a bit. I doubt going up 5 is going to be noticeable.
Going up 5 what? Please explain?

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Originally Posted by KBS View Post
One of the issues with chryslers 4..7 was that the piston did not shed heat to the block enough. This made synthetic mandatory.
Oh so synthetics base stocks make things cooler? Oh please explain this also.

And how does a synthetic formulations using Group III, IV and V differ in cooling capacities?

I am so interesting in learning new things.
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Old 12-25-2019, 03:34 PM
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I mentioned the 4.7 info because unless you are trying to get less piston friction with a high performance build or follow what the car manufactures are doing ,new piston technology is not well known. I would not personally make a vehicle unreliable to increase performance unless it was a race car.

Oh so synthetics base stocks make things cooler? Oh please explain this also.

It does not make it cooler but the oil stays in a liquid state at higher temperatures. 4.7's literally cook the oil.

Going up 5 what? Please explain
5 units in saybols or whatever the metric is that oil uses for viscosity.

And how does a synthetic formulations using Group III, IV and V differ in cooling capacities?

I assume that unless RoyalPurple , Amsoil ,Redline etcetera are used in the conversation that it is understood that Grade 3 or the highest grade refined oil is being referred to as 'synthetic'.

Incidentally ,the issues with toyota's buring oil was the oil rings. If the car had under 100k on it and you brought it in for oil burning ,the dealer would replace the rings even if the warranty was up at no cost. This supposedly was a unwritten policy.

I don't think it's a coincidence that many new cars have oil burning issues and pistons are no longer skirted flat tops any more. It's that or all of these manufactures have the same ring contractor that is cutting corners on quality. Car manufactures always know at some level that they are building junk.

Last edited by KBS; 12-25-2019 at 06:15 PM.
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  #30  
Old 12-26-2019, 11:18 AM
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Quote:
Originally Posted by KBS View Post
I mentioned the 4.7 info because unless you are trying to get less piston friction with a high performance build or follow what the car manufactures are doing ,new piston technology is not well known. I would not personally make a vehicle unreliable to increase performance unless it was a race car.
First the smaller skirts on piston, have nothing to do with friction. Friction is a
function of force and material not surface area. You should have learned that
in HS Physics class.

"Kinetic friction
Kinetic friction, also known as dynamic friction or sliding friction, occurs when
two objects are moving relative to each other and rub together (like a sled on
the ground). The coefficient of kinetic friction is typically denoted as μk, and is
usually less than the coefficient of static friction for the same materials.
However, Richard Feynman comments that "with dry metals it is very hard to
show any difference." The friction force between two surfaces after sliding
begins is the product of the coefficient of kinetic friction and the normal force:
F(k) = mu * F(n)."

Smaller pistons are to reduce the rotating mass of the engine and squeak out
every tiny bit of fuel economy.

Quote:
Originally Posted by KBS View Post
Oh so synthetics base stocks make things cooler? Oh please explain this also.

It does not make it cooler but the oil stays in a liquid state at higher temperatures. 4.7's literally cook the oil.
Bullshit, again some facts.

- API Group I and Group II base stocks are considered conventional base stocks.
- API Group III is in the US considered synthetic, this is due to case law and
not chemistry. Mobil v. Castrol, 1997(ish).
- API Group IV synthetic hydrocarbons
- API Group V is a catch all for anything that does not fit above, including
esters and naphthenic base stocks, etc. etc. (both petroleum and synthetics)

Now most engine oils today are formulated with Gp II, III and IV base stocks.
All of them used in engine oil formulations have flash point around 400°F and
fire points around 500°F. The differences in flash and fire points are do to
refining or manufacturing processes and for Group II and III their crude oils
sourcing.

So the physical state of the lubricant is independent of the API group used to
formulate it. Whether it is a Synthetic or Conventional...

Quote:
Originally Posted by KBS View Post
Going up 5 what? Please explain
5 units in saybols or whatever the metric is that oil uses for viscosity.
Well there are 2 prevalent units used in measuring kinematic viscosity today.
Saybolt Universal Seconds (SUS) and centiStokes (cSt). cSt are derived from
the metric system. But your "5 units" is really showing you don't understand
the system. As most of the world uses the SAE engine oil viscosity standard
standard SAE J 300, where the grades are given numbers that are not based
on either kinematic viscosity measurement system.

Please reference the chart attached. I will add that the SAE J 300 standard
only addresses viscosity grades of engine oils and not performance or service
grades.

Quote:
Originally Posted by KBS View Post
And how does a synthetic formulations using Group III, IV and V differ in cooling capacities?

I assume that unless RoyalPurple , Amsoil ,Redline etcetera are used in the conversation that it is understood that Grade 3 or the highest grade refined oil is being referred to as 'synthetic'.

Incidentally ,the issues with toyota's buring oil was the oil rings. If the car had under 100k on it and you brought it in for oil burning ,the dealer would replace the rings even if the warranty was up at no cost. This supposedly was a unwritten policy.

I don't think it's a coincidence that many new cars have oil burning issues and pistons are no longer skirted flat tops any more. It's that or all of these manufactures have the same ring contractor that is cutting corners on quality. Car manufactures always know at some level that they are building junk.
The correct term is API Group III not grade 3.

Now the engineering and design of the engine is mostly like the issue but
that is being driven by CO2 emission requirements being handed down by
our governments and have little to do with good engineering practices. Your
vote matters, be careful who you vote for...

I cannot comment on particular lubricant manufacturers, suppliers or
particular formulation. As I have worked for and currently working with many
of them. I am a chemist in the industry and have about 30 years experience.
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