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2005 Forester LLBean
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Discussion Starter · #1 ·
Hi, i I have an ‘05 LL Bean edition Forester. I accidentally purchased 5W20 engine oil instead of the 5W30 that is suggested. Are there down sides to using a different oil than is recommended? This car goes through so much oil I have to keep some in my trunk at all times.
Thanks in advance,

Alec
 

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1999 A/T - 235,000 mi. WA state
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890 Posts
5w-30 is recommended; hope you kept the receipt ...
 

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2008 LL Bean (4EAT)
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... ‘05 LL Bean edition Forester. I accidentally purchased 5W20 engine oil instead of the 5W30 that is suggested. Are there down sides to using a different oil than is recommended? This car goes through so much oil I have to keep some in my trunk at all times...
I have the same engine. At 70,000 miles, it burns no measurable 5W-30 between 2500-mile changes.
If you have high miles, and your consumption of 5W-30 oil is high, you should increase the viscosity to 10W-30 or 10W-40. There is no harm in using the 5W-20 by mistake, but it will only increase your oil consumption.
 

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2019 Forester Sport Lineartronic® CVT
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351 Posts
Is it leaking it?

If I use a quart of 5w20 to top off this time, I'll use 10w30 or 10w40 next quart. That's in my older '95 Ford Thunderbird that uses oil a little. My aim is 5w30 but I have some few quarts of 5w20 left over that I will use in it.
 

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2007 Forester Sports XT 4EAT
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40,886 Posts
@alec120psi 5W20 might work for you in the winter, but not recommended for hot weather use. If you can't return it, as other's have noted, use it for topping up in between oil changes.

Bobby...

2005 owner's manual - "Maintenance and service", 11-15:
554126

['07 FSXT Member Journal] ['03 X Member Journal]
 
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2017 Foz 2.5i CVT
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If you can't return the oil, another solution I might propose is to buy an equal amount of 10W40 and mix your changes half and half with 5W20 and 10W40. That should give you an effective weight right around 7.5W/30 :) If your engine is using oil, putting a thinner oil into it is not a good approach IMO.
 

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2019 Crosstrek 2018 Forester XT
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You should use 10W-40 100%
 

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2005 Forester LLBean
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Discussion Starter · #9 ·
I have the same engine. At 70,000 miles, it burns no measurable 5W-30 between 2500-mile changes.
If you have high miles, and your consumption of 5W-30 oil is high, you should increase the viscosity to 10W-30 or 10W-40. There is no harm in using the 5W-20 by mistake, but it will only increase your oil consumption.
I do have high mileage 171K. It will easily go through a quart of oil every 3k miles.
 

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2005 Forester LLBean
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Discussion Starter · #10 ·
Thank you everyone for your replies and knowledge. I will try to return the mistake oil and will pick up some 10W-30 tor 10W-40 to try to decrease my oil consumption.

Thanks again,

Alec
 

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2017 Foz 2.5i CVT
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A quart in 3k miles is actually low consumption by my standards from the old days. If you have seeping seals, try some high mileage oil...I love Valvoline maxlife syn blend and have used it in older cars with much success.
 

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2015 ; 2.5i ; 15,000 Miles (I drive a lot less than I used to !!!!)
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Hi, i I have an ‘05 LL Bean edition Forester. I accidentally purchased 5W20 engine oil instead of the 5W30 that is suggested. Are there down sides to using a different oil than is recommended? This car goes through so much oil I have to keep some in my trunk at all times.
Thanks in advance,

Alec
As it uses the thinner oil, just add the correct type; just be sure to monitor dip-stick closely till you are certain that it has all been cycled thru consumption ; your 5W20 will "age" thru 5W21; 5W22; 5W23; 5W24; 5W25; 5W26; 5W27; 5W28; 5W29; and will finally be equivalent to 5W30 after ... about 10 quarts of 5W30 !!! Or, until after you reach proper mileage to to complete oil change. Just keep your driving within the proper spec for the type of oil in your engine ! I would NOT recommend any type of high performance operation while "adjusting" your operating oil !!!!
 

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2005 Forester LLBean
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Discussion Starter · #14 ·
Thanks everyone. I was able to take it back to O’Reilly and picked up the correct one and changed the oil yesterday.
 
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