5w-20 or 5w-30? I've heard thing about both..
 

Manual says 5w-20, however I've read that Mazda CA recommends 5w-30, and so do many forum members here. What would be best for me, assuming I'm in Florida?

Florida?

20w50

Im in NYC, 20w50 Royal Purple mixed with 1-2 quarts of Mobil1 15w50. cP rating for RP 20w50 is 18800 @ -20 Celsius. Thats about -4 Fahrenheit, and Im nowhere near that. the coldest night ist just 16 Fahrenheit. Im good.

Many believe that Mazda's recommended 5W-20 (even 5W-30) is too light an oil for the engine. And, it was recommended only in an attempt to get the best EPA gas mileage figures.
I've started using 10W-40 and I'm much further north than you.

I use castrol 5w-30 non synthetic. change every 3k and my 8 runs just fine. ;)

^+1

Alright, 5w-30 looks like the ticket. Mazda said something about some special so and so thats supposed to be in the oil for the Renesis? Its some three or four letter acronym that I just can't remember. Do I need to look out for that?

I started to pre mix at 40k. it just for extra lubrication so theres less friction on the apex seals.

+1 Castrol 5w-30 non-synthetic high mileage for that lil bit extra. I ran it on my previous 8 and compression was good at 36K miles.

I premix as well though to make up for that missing middle oil injector that they left out on the 03-08 Rx8 models.

I'd be surprised if any part of Mazda officially goes against the corporate recommendations, though I've read plenty of owner reports where Mazda service depts use 5w30; most likely because it's what they have on hand (my guess).

Guess what, there is no data that I know of, that gives any statistically meaningful direct correlation between viscosity and engine life for the Renesis. The population size is just too small and Mazda does not let local shops do tear-downs of failed engines to determine cause of death. What we do have are a handful of rebuilds by longtime rotary mechanics. Read and make up your own mind.

In truth, I get the feeling that type and viscosity probably doesn't make a whole lot of difference for commonly-used ranges (0w20 thru 20w50). These engines die early deaths, by piston standards, and some of the leading killers (insufficient cooling and carbon buildup) aren't mitigated to any major degree by viscosity selection. There are indications of bearing wear, but no direct corelation between bearing wear and engine failure has been demonstrated, or even any hard evidence of superiority of one viscosity over another in regard to the bearing wear. Imho, the wear probably has more to do with removal of ZDDP than it does with viscosity. In my opinion, you'll get far more benefit from pre-mixing, periodic redlining, and regularly changing the coolant.

But it sure is fun to speculate :D

OP....................that's about the third thread you started on subjects that have been covered at great length. I'm surprised that you haven't been flamed yet. Might wanna learn to use the search function before randomly throwing out a thread. A little reading goes a long, long way. :yesnod:

people these days want quick answer so they dont have to use their brains.

this is just sad ...

Hope you're just not re-reading my redundant accounts of how my dealer switched from 5w20 to 5w30. :)

IMHO, the definitive info on appropriate viscosity is contained in the excerpt from the Australian owner's manual that ASH8 posted a while back, and that a few of us have re-posted. If you're not at extremes (arctic or tropical) there's a wide range of oils that work. I don't think anyone has posted a choice that isn't OK. Then it comes down to belief.

Ken

I use vegetable oil.

No really.

really?

Which brand u recommend? so I can go grab a few for myself
:rock:

No oil for you!

Closed.

The Oil Nazi.