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Guest Message by DevFuse

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H6.3.0 Fuel requirements

Premium fuel ethanol 6 cylinder 2003

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4 replies to this topic

#1 To NY



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Posted 07 October 2013 - 01:49 PM

I just purchased a 2003 Legacy Outback with the H6.3.0 engine and VDC. It has 74,500 milkes. This is my first Subaru and I really like it. To my chagrin, I learned that it requires premium fuel and NO ethanol.

What has been other owner's experiences? Why is the ethanol bad if the octane rating is acceptable?

I would appreciate any comments. Thanks.

#2 idosubaru


    Elite Master of the Subaru

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Posted 07 October 2013 - 04:50 PM

i think it's "recommended", not required...or that varies by year, so check.  i don't think ethanol makes any difference at all - where did you hear that?


in any event my 02 and 03 H6's...and many others...have 210,000 and 170,000 miles and run perfectly on the *cough* killer 87 octane and ethanol blends i feed it.  i've given it high octane non-ethanol blends when towing and noticed no difference.

#3 CNY_Dave


    03 LL Bean H6

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Posted 07 October 2013 - 04:50 PM

I have never seen a warning against 'normal' amounts of ethanol for the H6, up to 10% should be fine.


It does not 'need' premium, it runs fine but with less power on 87, with the caveat that there have been reports of excessive carbon build-up with lower octane fuel.

#4 3Pin


    Eat, Live, Breath Subaru

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Posted 07 October 2013 - 10:57 PM

I give mine mid-grade and sometimes 87.  Seems to run a bit faster with the higher octane stuff.  118K on mine and loving it.

#5 To NY



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Posted 08 October 2013 - 02:54 PM

Thanks for all the comments. Both my mechanic and the dealer said the same thing. The manual also recommends non-ethanol premium. Non-ethanol is getting increasingly hard to find particularly in the northeast.

I also have a McIntosh sound system and it has great sound but the CDs tend to skip. Any comments?

Also tagged with one or more of these keywords: Premium fuel, ethanol, 6 cylinder, 2003

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