Just bought a rx-8 yesterday and wondered what kind of oil i should use for this car?? Manual kinda doesn't fully explain. Anything else i should watch out for other then burning through oil??? its a 04.

 

5W20, you need 5 bottles, but check the level after 4.

S

 

do I just use what ever or should I use synthetic oil.

 

hotly debated subject there, mazda doesn't recommend using synthetic, but many people do, same as they don't recommend using regular fuel but many people do. it just depends on your liking and what is available to you and how your car reacts to it. Some people also put a little bottle of 2-stroke engine oil in the fuel too to add that extra lube to the rotors and to help keep the engine free from carbon build-up. marvel mystery oil might be used for the same purpose but I haven't run into anyone here that uses it.

I'd recommend using the best brands out there for the rotary if you want it to last a long time. not all oils are made the same. royal purple seems to be popular among the people here.

oh and you might want to visit the forums over at www.bobistheoilguy.com, very useful source of info.

 

Is your car new? Stick to normal oil if it is, then use synthetic when it's broken in.

 

no its one year old but its a 04 that was sold in april of 05. Thanks for the info.

 

Try Castrol 5W 20.....Pretty Good oil
Smoother ride....

 

didn't read the FAQ section huh, lazy bum

 

Unless you go through the hassle of trying to drain the oil coolers (not necessary), the refill capacity is 3.7 quarts with a filter change. A lot of people here use synthetic with no problem, I have always used synthetic in my cars but not this one. The way I see it, if Mazda recommends against it, I'm not going to use it. I use Penzoil 5w-20. If Mazda ever clears the car for synthetic, I'll switch.

 

I am currently running synthetic in all of my vehicles, except this one. I am with stickman on this one. Mazda says not reccomended, and the fact that a fair amount is burnt in the cylind...er, combustion chamber, I will stick with Dino. Castrol 5w20 by the way.

 

Mazda doesn't recommend against synthetics. Show me where it says it in the manual. It says nothing about type.

 

The manual is not specific. However, The RX-8 Product Update DVD says synthetic oil is NOT recommended.

If you know more about the Renesis engine than Mazda engineers, by all means, use whatever you like. That goes for gas choice too.

 

this has been debated for a while now within the members... Mazda North America says not to use synthetic oil due to the fact that its very thin oil, which means potencially the oil won't last long becuase the rotary engine will eat that up, but there really hasn't been any proof of it, but Mazda just wants you to be safe.... Bottom line use what you want!Heres some you can use:

Mazda Certified from the dealer 5w-20 (Non Synthetic)
Castrol GTX 5w-20 (Non Synthetic)
Valvoline 5w-20 (Non Synthetic)
Pennzoil 5w-20 (Non Synthetic)
Royal Purple 5w-20 (Full Synthetic)
Mobil 1 5w-20 (Full Synthetic)

 

I don't think it's quite that cut and dry as to who knows more. I think it's really more a matter of some synthetics behaving more compatibly with the rotary than others. Early synthetic formulations were "bad" on apex seals and this is primarily no longer the case - for the most part - though there COULD possibly be some that MIGHT cause problems.

Now this is just speculation but it may be more of a case of Mazda deciding that it's more "appropriate" to simply say use only conventional oil.. than to test out, verify, certify, and specify which synthetics are good to use.

However, reading though historical documentation and word-of-mouth accounts as to what kinds of synthetics have been used, for how long, and in what applications combined with my own personal experience tell me that there are some brands of synthetic oils that are fine to use in the Rotary. Im sure if you had lunch with a Mazda engineer and spoke frankly, off the record of course, they would confirm what I have said.

But as I said.. this is just speculation on my part.

No, I don't know more than a Mazda engineer and never will - that's not my specialty. What I do know is that I personally use synthetics, as do others that I know, without problems.

 

Thats whats great about this country. Freedom. And you are free to experiment with your car however you wish. Good luck.

 

read this, very informative

http://www.mazdatrix.com/faq/synthetc.htm

 

I'm just about to do an oil change and have been told to switch over to 15w-40. Just wondering if anybody else has heard this, or ever tried it.
Thanks

 

15w-40 is what I use in the tractor's diesel engine at work, I don't think you can really hurt the engine by using a heavier weight oil... but it does have a higher viscosity and therefore it increases drag on the moving parts that get oil so you might get a small decrease in engine performance and fuel economy.

The first number (Xw) refers to how cold a temperature it can still be pumped at, the lower the number, the lower the temperature it can stand, the second number refers to the viscosity of the oil at engine operating temperature, the smaller the number, the lower the viscosity. If the renesis can run with 20 grade oil then going any higher is just increasing drag, however a higher weight oil might also reduce wear a bit as well. a 10w-30 sounds like a good compromise for summer running,

BUT... (again) if 5w-20 works why change, if you change the oil you'll still have the old stuff trapped in the oil cooling radiator so you'll end up with a mix in there.

 

the only problem i've had with 5w-20 was one time in the winter the car decided not to start, it acted like it was flooded and took about 15minutes to start up again. I talked to a guy who has worked on some rx-8 and he told me that they have always used the 15w-40 stuff because it seems to work better with that engine and then only reason that mazda recommends the 5w-20 is because it saves on gas a bit. Then a guy at work who works on all kinds of cars (mostly audi's) told me that he has always been told that 15w-40 was the best oil to use in my 8 aswell. Just want to get the best performance out of her.
thanks

 

Does synthetic oil burn the same as organic oil? Synth oil is advertised as not breaking down as quickly as organic oil...better thermal breakdown or whatever?

Glad to know castrol is recommended. I've always had good results with that.

 

you newbies really need to read up on the FAQ thread to learn more about this whole RX-8 and oil deal...... tons and TONS of discussions on this already...

 

Many of us use synthetic oil. Works just fine. I use 5w-30 in mine (turboed though).

 

Synthetics are brewed from methyl esters that decompose at about 400°. As good of a lube as they are prior to decomposing, afterwards they loose most of the good lube properties they had. They burn pretty cleanly, better then normal oil.

Castor oil used in 2 strokes (de-gummed!!!) breaks down at about 600° and leaves a varnish behind thats kind of like a dry lube. I don't think I would want that residue forming in the seal lands. It's not bad for a 2 stroke since pistons are replaced often.

No doubt folks will experiment and it will be interesting to see what they report.

 

I buy Castrol GTX 5W-20..........manual doesn't recommend synthetics and I treat the manual like the bible.................

 

Mazda recommend people to put premium gas.

Mazda recommend people to use ONLY Mazda parts.

Who actually listens?

For me, No matter what car, I always put premium, yeah it sounds like a waste but even my father's 1995 Quest GXE use Premium. So First rule does NOT apply to me (Im not listening to Mazda, Im just doing things that I usually do, and it happens to be the same as Mazda)

Second one, HELL NO ! Only Mazda parts? wait a minute, I have K&N Typhoon Version 2, RB Ram Duct, and Toyo Proxes 4. they all NOT OEM parts, so ?

Gear Oil I use Royal Purple Gear Max 75W90

Engine ? I tried QuakerState Advance Q, Castrol Syntec, and Royal Purple . All FUll Synth. Still running strong.

and Guess what Im doing right now. Im ordering my Next case of Royal Purple ~