2004 Subaru Impreza 2.5 NA recommendation

[brian]

Hey all, I bought a 2004 Impreza with a 2.5L N/A engine and 107Kmi. I started off with Auto-RX an Castrol GTX 10w-30. I'm coming to the end of the 'rinse cycle'. I am thinking of using GC 0w-30, Mobil Delvac 5w-40, Amsoil 0w-30/5w-30/10w-30/15w-40. I am wondering what oil has the best results in this motor? I also own a 2001 Jeep Cherokee, 1993 Dodge Cummins, 1982 Kubota 305DT, and 2006 Kubota RTV so 5w-40/15w-40 is already a given. Will I take a fuel economy hit with syn xw-40 in the Subie? Regards, Brian

 

[Titan]

Brian, there is no "best oil" for this vehicle. Any of those you listed should give good service. Any fuel efficiency differences would be minimal, unless you have a lot of short trips when cold...then, the 15W-XX oil may result in slightly less economy. But, at operating temperatures, the difference in viscosity between any of those stated Xw-30 weights compared to the Xw-40 weights is so small, it's going to be hard to measure.

 

[Pablo]

You may notice a very, very tiny difference, but IMHO unless you are the perfect robot driver, I doubt it. If you want to go over to the thick side, I recommend: Amsoil DEO 5W-40 Or drop down to: Amsoil AFL 5W-40 Amsoil ASL 5W-30

 

[Norm Olt]

Nothing in your post about your intended OCI? My experience with a '92 SVX is that just about any 10W-30 will give you both excellent protection & excellent fuel economy. IMHO it is more about the driver than the viscosity or brand of the oil vis-a-vis gas mileage: sure, a 0W-30 (where required) should give a little better gas mileage than a 20W-50, but... In the REAL WORLD it is the heaviness of the right foot & the formulation of the gas itself that make the most dramatic difference in gas mileage. My SVX (230 hp flat 6, also NA) still gets better gas mileage both in town & on longer highway trips than the EPA "guestimates", and that is on regular gas for the last 5 years or so. 28+ mpg on my last highway tank, I've gotten over 30 mpg at 80-85 mph on a cross-country trip 5 years ago... For 3K OCI's whatever semi-synthetic (i.e. Union 76 Super, Chevron Supreme, Maxlife, Havoline, etc.) is on sale or rebated is just fine. If you take advantage of the $0.99 after rebate PP or Synpower deals a longer OCI is well warranted. I've gone 7,500 on PP and am contemplating 10K in the future, based upon the stellar OA's typically reported for PP (in almost anything!) and most Subaru's in general. Cheers!

 

[brian]

I don't mind paying for expensive oil but I'd like to run it about 10-15Kmi. I run 10-12Kmi drains in my Jeep 4.0 and my Cummins B5.9. If I won't take a fuel economy hit running 5w-40 or 15w-40 in the Subaru that's probably what I'll use. That means I only have to stock one oil. :) Thanks,