Engine oil OEM Mazda or OEM Subaru

But then we replaced it with a SkyActiv Mazda3 that used 0w20 and proceeded to have a good long history with that motor that had 0 oil consumption in 125K miles; I did all of the oil changes myself and it was always 4.5qts in/4.5qts out every 5k miles.

For [Naturally-Aspirated Skyactiv engines](https://en.wikipedia.org/wiki/SkyActiv), it is highly recommended that you use Mazda's own(Idemitsu) high molly GF-5 0w-20. [Arguably it is one of the best oil for skyactiv engines](http://www.cleanmpg.com/community/index.php?threads/45295/#post-357910).

Oil being dark is a good indicator that you have to do an oil change. However, you shouldn't wait until it changes color to do it. Clear oil doesn't necessarily mean you can keep going.

It is well established that boxer engines want their oil changed and I do not think for a second that a visual inspection is valid for determining if it is time. Highly, **highly** recommend you change the oil per the manual without hesitation and regardless of what it looks like.

2014 3, 0W-20 full synthetic (whatever major brand is cheapest) from brand new, every 7500 miles.

170k, runs like a top, burns not a single drop between changes, compression and fuel mileage exactly the same as new.

I use Mazdas 5w-30 Ultra DPF. Mazda once said that this was the oil that they're using, so I guess what's used by mazda can't be too bad for the rex

I would also make sure that every time you fill up the gas you check the oil dipstick and if it’s a little low top off the oil. In fact, I think this is probably crucial to owning an older Subaru like mine mine has 300 K.

I second those saying bring a spare quart of oil. I wouldn't be too worried about taking my 2012 Outback at 170K miles on such a trip...but would agree check the oil every 1000 miles or every morning (depending how far you go in a day) just to make sure it isn't getting low.

Mazda’s OEM 5w30 is a little too thin for my blood considering the engine temps when driving hard, fine if you’re going to never redline the car

I have a slow oil leak (something like a quart every 1,500 miles). Dealer quoted just under $3,000 for the fix when it was 17 years old with 110,000 miles. I'll just buy the occasional quart of oil.