buwisit

hi, im planning to change my oil probably this weekend..
what kind of oil do u guys recommend??..right now im using GTX CASTROL 5w-20
should i switch to something other that 5w-20?

dozer

iTrader: (3)

ive been using 5w30 with no problems, engine runs great and feels fine

buwisit

that's great..
i always have doubts in using oils
lOL..
i wanted to change my oil right away cause i have this coupon and i wanna use it b4 it expires..
so you recommend using 5w-30?

nycgps

iTrader: (1)

Search.

Or just

Read my sig.

Huey52

iTrader: (2)

nycgps has convinced me to go 5w-30, in my/our area, in the future. Read his links.

There is some small gas economy in using 5w-20 (which is why it's RX-8 recommended; and also my Jeep Patriot, to increase the manufacturer's fleet average), but at the potential expense of increased wear due to its relatively thin viscosity.

Warmer climates should go 10w-30 or 10w-40.

edit: I also pre-mix 4 oz./tank Idemitsu, but that's a whole nuther [2-cycle] oil discussion.

buwisit

fair enough..
i think my head just exploded for reading those sig of yours nycgps
nice info u got there

Renesis07

iTrader: (1)

I use 5W20, I have 72K with no problems.

ndhoffma

I have used 5w20, however I think I will be changing to at least 5w30 for the summer after doing some reading.

Sleepy-z

Mazda reman uses 5w-20(non synthetic) on the rebuilds. Personally I am a believer in whatever the conditions call for, I tend to use lighter weights in the winter and a little heaver in the summer. Totally depends on the climates though imo, freezing winters to really hot summers is when I alternate. I dont know the technical break down on oils but I always figured the thicker it is in the hot climates the more it would protect/not break down as easy.

risky business

10-40 ftw. ( if you live in a hot climate)

ken-x8

I think my dealer read your sig. Last two changes they used 5w30.

Ken

New Yorker

I suspect the difference between using 5W-20 and 5W-30 is not significant, so I'd say read the threads, listen to the arguments, and use what you're comfortable with. I use 5W-20; here's why:

• It's the oil that Mazda, the company that designed the engine, recommends in the US, which is where I happen to drive my 8.

• If 5W-20 doesn't sufficiently protect the engine—and leads to costly premature engine problems—why would Mazda recommend it? The money Ford saves by incrementally lowering fleet MPG would easily be offset by the not insignificant cost of repairing/replacing engines, and worse—the reputation of their flagship vehicle. In fact, an unreliable Renesis could've cost Mazda not only the RX-8, but the very future of the rotary engine. That's a helluva lot to risk for a tiny bump in mileage.

• Mazda bent over backwards to make the Renesis reliable; one of the reasons Mazda doesn't offer a turbocharged Renesis is to reduce the probability of engine problems. If increasing reliability is so important, why jeapordize it with the wrong oil?

• Who says 'fuel economy' and 'full engine protection' are mutually exclusive? Over time, motor oils keep getting thinner; modern motor oils may well be capable of both. Fancy that.

• Let's assume, for a moment, that 5W-20 was too thin for the Renesis. In 2009 Mazda modifies the engine to make it even more reliable. So… after 6 years of production and real-life testing with thousands of US RX-8s—and spending who knows how much to modify the Renesis for increased reliability—what oil does Mazda recommend for the new, modified Renesis? (Remember, this is Mazda's "chance" to get the viscosity "right".) Yup… 5W-20.

• Cold startup is the toughest thing on an engine; for the kindest, gentlest startup, think thin.

So yeah, I use 5W-20. Not that I've given the question much thought.

dshiznit1489

I'm using 20w-50

05rex8

iTrader: (7)

I'm using a 1,000w-50,0000 oil.

seriously...enough with the oil threads.

Davey's RX-8

iTrader: (1)

I'm using AstroGlide.

AAChaoshand

5w-20 here and 5w-30 in japan from what I understand, do what your manual tells you to do otherwise getting something fixed under warranty is going to be even harder than it was before you changed.

zoom44

plenty of threads about this to read. closed