Petscar

I know, this subject has been beat to death but I want opinions from people I know on the current forum. Currently using 5w 30. Thinking of going to 10w 30. I take the car off the road in winter.

vvette

Why do people not listen to MAZDA engineers especially for this car? Everyone here will say this and that but none of them designed the engine... If your not racing it, Stick to what the manual says..

Loki

iTrader: (1)

Because the same engineers designed the coils and other questionable components on this car. It's been 15 years, we've learned a thing or two the hard way. Don't get me wrong I'm all for following manufacturer specs but not blindly so.

The change from 5w to 10w makes almost no difference, it's only in play when the oil is cold. If you don't winter drive, 10w is fine.

vvette

LOL, thanks but you're not an engineer and things have changed yes, but the engine has NOT. Therefore, its is more imperative to spec what was used when the engine was designed. (If as you say makes no difference....why do it, makes no sense.)The manual is the Bible and if you want to play Monday QB, good luck.. Stick to what the manual says.

Loki

iTrader: (1)

Are you sure I'm not an engineer?
While you're reading the manual please refer to the scale of viscosities recommended for different climates and use conditions. You may be surprised to learn that the manual recommends different grades of oil depending on conditions, with thinner oils for colder climates.
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The same engineers also recommend different viscosities outside the US than in the US, likely for emissions reasons.

Following a book blindly gets a lot of people into trouble

CaymanRotary

I’ve always run 10w-40 conventional in these cars. I never had any engine problems in any RX8 I’ve owned so it’s not going to hurt it. The argument for thicker oil is that it would be better for the bearings. Mazda was more interested in keeping emissions lower than they were the longevity of the engine.

Petscar

I'm guessing your the kind of person who doesn't question things. Thinking outside the box has led to great innovations. If Mazda engineers didn't screw up the engineering of this rotary, then compression issues would be far fewer. Let's not forget the multitude of other design flaws. Coil design is just one more example of many. That being said, just how much faith can you put into their oil recommendations? More good info has come out of experienced owners for the improvement of keeping this car healthier than Mazda.

dannobre

iTrader: (3)

5-40 full syn for me..... it's more important that it has oil in it than freaking put about 5-20 or 5-30. LOL

Loki

iTrader: (1)

A pilot friend of mine once bent an aircraft in a rough landing while following the manual on approach speeds for those conditions. Turns out, good engineers make bad decisions. Nobody here is trying to change your mind vvette, if the manual makes you happy, great. Let "the rest of us" do as we please.

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dannobre

iTrader: (3)

This is going nowhere fast...


No personal attacks or animosity is allowed

jcbrx8

As Loki & Cayman said...you do realize that OEM engineers spec engines for organizational priorities which may or may not be a priority to a consumer, e.g. emissions, right? Could it be possible that Mazda engineers spec'd 10w-30, which is acceptable, but perhaps not optimal; to meet their emissions goal? However, over time Renesis owners / enthusiast have discovered that 10w-40 better lubricates the engine. Certainly the manual 10w-30 will get one to the 3 yr/ 36k mile warranty recommendation while meeting Mazda's emissions goal, but is it optimal for engine longevity? Similar discussion for mineral vs synthetic, i.e. cleaner burn vs. slicker affect. Many enthusiasts, myself included, run full synthetic in our beloved engines, which is a big no no according to the manual.

End of day...for sure the manual s/b considered the base of knowledge, but to disregard the experience of owner / enthusiast's, some of whom m/b engineers, experience over the course of more than a decade and a half is...well...w/respect close-minded.

btw I run Mobile 1 0w-40 full syn.

CaymanRotary

Couldn’t agree more. This is an enthusiast car with a unique engine. The manual is a helpful tool but isn’t the end all, be all. Just make sure the car has oil in it more than anything. I use the oil I like because it’s worked for me and have yet to encounter any engine issues on any of my RX8’s. Other people I know have had engine issues though (not sure what oil they ran).