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rouppe
By rouppe | AA Member | 11 Posts | 2 June 2019 at 10:54am

I have a NZ new 2004 Subaru Outback 3.0R Limited. It is fitted with iridium plugs which only require changing every 100,000km. Which is just as well given the effort required to change them.

When I bought it the car dealer said it would run fine on 91 Octane, however there was a "premium fuel only" sticker on the fuel flap so I've only ever used 95 (and occasionally 98) octane fuel, partly because I thought this type of spark plug would foul with 91.

Is this the correct fuel, or have I been wasting 15c per litre all these years?

Anon
By Cade | AA Expert | 3937 Posts | 5 June 2019 at 10:11am

Hi there,
Until recently most Subaru cars required 95 or higher octane fuel, even more importantly if they were turbocharged. A lot of them would "pink" a bit when run on 91 octane fuel- the plugs wouldn't foul (usually would happen if over fuelling occurs- ie, faulty temp sensor) Personally I would run an H6 engine on 95 min Octane fuel for best results.