Hi guys, and gals. Was just wondering which brand of motor oil are you going to use in your RX8. Also do you plan on staying with 5w-20 or maybe going with a heavier weight?

 

I was planning to use Mobil-1, once the engine is broken in. I would like to see the owner's manual to see if Mazda has any recommendations on what kind of oil is best for it.

 

Mazda recommends using 5w-20 also recommends not to use Synthetic motor oil.

 

Name brand - I'll probably go with a top name brand. Pennzoil, Castrol, or Kendall, etc. I don't think it makes much of a difference unless you bought some unfamiliar name brand (ie. generic).

I plan on using the 5w-20 weight, only because that is what Mazda recommends. Especially during the warranty period. After the warranty period, I may use a different weight. And during emergencies (if I'm on the road, and I can't find that weight), I won't be particular on brand or weight if I absolutely needed it. That shouldn't be a problem since I usually care 1 or 2 extra quarts with me at all times.



On a related note - I have a question, and I'll call upon either Quick_lude, the "legend in his own mind oil expert" , or someone else. Anyway the question:

Many years ago, a friend or relative (don't remember now) told me that they prefer "Appalachian" oil (i.e. Kentucky, Pennsylvania oil versus the Texas brand oils. Something about the "Appalachian" oils contain less grit than the "Texas" oils. It sounds like hogwash to me, but I'm no petroleum expert. Is this propaganda, rumor and/or just plain BS?

 

Haha.. far from it.. :D

Honestly when it comes to rotary engines and oil I'm a newb just like most of us. I still haven't been able to figure out if synthetic oil would be ok to use in this engine.

As for the 5w20 that's a tough one. On one hand you are forced to use it at least for the warranty period "just in case".. although unless someone really neglects the oil, ie doesn't check/top up and the engine blows, it wouldn't be because of the weight but because of lack of oil.

But on the other hand the ONLY reason North American automakers went to 5w20 oils is CAFE. NO OTHER REASON but to reduce overall fleet fuel economy to meet CAFE targets. Personally I wouldn't use a 20 weight in my current piston engine since I do track and auto-x with a lot of 6-7K rpm driving. My motor would chew that right up so I use Mobil1 0w40 which is standard fill on all Mercedes AMG vehicles and some others like Porsche, etc. I don't know enough about rotaries and how "hard" they are on the oil if you keep revving them to 9K rpm.

I'm still curious what oil viscosity is recommended in Europe and Japan. If it's a thicker oil like 5w30 or 5w40( 5w40 is the most often grade recommended in Europe for piston engines while same engines in NA are recommended to use 5w20, CAFE again) then I would use 5w30, especially if I was planning to keep this car for a long time.

 

An earlier post says that synthetic oil is not recommended. On page 8-9 of the owners manual it says " Energy conserving oils are recommended" . Also it has the interval of changes at 6 month, or every 5000 or 7500 miles depending on your driving habits and environment. Isn't energy conserving oils synthetic?, and wouldn't the interval of 5000 to 7500 imply that synthetic was in it and recommended? I don't think any dino oils recommend these long interval. Anyway that just a couple observation I've made from the owners manual, while not driving my winning blue 8 around northwest florida.