Which grade for the least consumption?

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Continuation of this: https://bobistheoilguy.com/forums/t...mption-updated-at-post-64.336079/post-6219232

FB25 Forester. After running 1 qt of @High Performance Lubricants Engine Cleaner 30 for 2000 miles, the oil consumption is significantly reduced: only 1/4-1/3qt of oil was lost during this timeframe. Normally this engine drinks a full quart of 0W20 every 2500-3000 miles.

I’ll assume the HPL Engine Cleaner helped unstick the rings (to an extent) and I would like this process to continue.

I have 3 of their oils in my inventory:

Standard PCMO 5W20
Standard PCMO 10W20
Standard PCMO 5W30

Which one is likely to result in the least oil consumption? Note: this vehicle may see some cold temperatures during winter months, but it will not be below 0F.
 
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10w-20 to answer your question but considering winter temperatures, 5w-30.

Begining with quart every 2500-3000 was not bad enough to get concerned about.
 
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I would say the 5W30 would reflect less oil consumption however I believe the engine would last longer with 5W20. I did not read the entire article however the best direction would be use whatever the factory recommends for the vehicle.
 

Shel_B

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I would say the 5W30 would reflect less oil consumption however I believe the engine would last longer with 5W20. I did not read the entire article however the best direction would be use whatever the factory recommends for the vehicle.
Why do you say that? What's your reasoning?
 

The Critic

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Given this is a DOHC chain engine I would be more than tempted to run a thinner Euro oil like M1 FS 0w40.
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I will say that Subaru allows 5W30 or 5W40 as an alternate grades, temporarily. I can probably "explain" the use of 5W20 over 0W20 to the owner. Explaining 0W40 might be a bit more difficult.
 
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Why do you think a different viscosity grade will keep oil rings from sticking?
Pretty sure that we have all come to the conclusion that it's the base stock and VII's that makes that difference, regardless of viscosity.
 

The Critic

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Why do you think a different viscosity grade will reduce oil rings from sticking?
I don't. I plan to continue using HPL's oils in this vehicle to assist with cleaning the piston ring deposits.

Within the inventory I have, I was curious which oil would be least prone to oil consumption.
 
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I don't. I plan to continue using HPL's oils in this vehicle to assist with cleaning the piston ring deposits.

Within the inventory I have, I was curious which oil would be least prone to oil consumption.
Doubt there would be much of a difference between those that you list. 5W-20 would be my choice since I like to keep the viscosity spread to a minimum, while still maintaining the fuel economy provided by a 20.
 
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Doubt there would be much of a difference between those that you list. 5W-20 would be my choice since I like to keep the viscosity spread to a minimum, while still maintaining the fuel economy provided by a 20.
Have you tried other grades and found that 20 provides better real-world fuel efficiency?
 

Shel_B

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Doubt there would be much of a difference between those that you list. 5W-20 would be my choice since I like to keep the viscosity spread to a minimum, while still maintaining the fuel economy provided by a 20.
With that reasoning, why not the 10W-20?
 
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