Doneman

I just brought a used RX-8 with only 17.8K miles, and i know I'll need an oil change at 20K (according to the manual). The older RX-8 (series 1 '04-'08) required the 5w-20 and would void warrenty or something liek that. What about the new Series 2 (09-10)? What is the best performance oil for daily driving and occasional long trips (cuz cities in Texas are normaly 3 hour drives apart)?

a) have dealer keep putting in 5w-20

B) see about the dealer putting in something else
B1) suggestions on alternative oil and brand if dealer will put it it

paimon.soror

iTrader: (15)

General driving 5w-30
Frequent Long Tripcs 5w-20

Dont mention anything other than 5w-20 to dealer
Dont mention anything about synthetic to dealer

Doneman

wait, how is 5w-20 better for longer drives in the heat? i thought the general rule was it was better for track racing only?

you say not to mention synthetic, why's that? are all teh 5w-20 and 5w-30s fully synthetic?

paimon.soror

iTrader: (15)

In theory they recommend 20 because it gives you better gas mileage during long trips, this is why it is a Mazda recommended oil weight, to help their fuel economy and emmisions tests in the US. However, using 30 weight for daily use has proven to be more effective for rotary engines because it's thickness provides more protection by providing a thicker film and higher shear strength than the 20 weight.

As far as not mentioning synthetic, the reason is because depending on the dealership, mentioning that you are using products for the engine that are not recommended by Mazda of USA may void your warranty. For example, if your motor fails and you tell them you have been using synthetic oil, they may turn around and say that you are at fault of the failure because you used non-recommended oil.

With the cost of maintainance of an RX8 and engine replacements that Mazda has been doing, they wont hesitate to find any and every reason to not put the blame on themselves when something goes wrong.

Lastly, in theory yes, today's conventional oil does have a degree of synthetic blend added to it, although much less than "synthetic blend" and "full synthetic" oils.

MoonieGT

I'm no expert, but I thought I read somewhere that you should not use synthetic in a rotary... anyone else heard that before?

paimon.soror

iTrader: (15)

Well there are at least 1000 threads all over the internet covering this. There are many people who abide by it, there are many people who wouldn't touch it. Mazda race team uses synthetics on their rotaries; Consumer Mazda says not to use it.

The general key comes to this: Whatever oil you are using, make sure it is of the best quality that you can use. Make sure to use the proper grades, and make sure to change your oil frequently. Use premix in your gas, and always make sure the engine is warm before dicking around.

If you follow the above steps I am sure that it wont matter whether you are using synthetic or dino, you will have a nice long lasting engine.

terch1

iTrader: (2)

Series 1 or Series 2 = same engine thus same oil. Read the f-ing manual!!!!!!!!!! Or you can read the hundreds of posts regarding this very issue as stated by others.

xexok

Out here when I asked the dealer if they would put in 5w30 they said no problem, it would just be an extra $10. I didn't bother and just got 5w20 because that's ridiculous, but at least in my area they are willing to do what you ask if your willing to pay more.

When I start to do my own oil changes soon I will be using 5w30 though.

9krpmrx8

iTrader: (46)

Okay, there is some misinformation here. Oil type, weight, etc. means nothing if you do not change it often.

5W-20 is a synthetic technically but there is some debate as to whether a semi-synthetic is really a synthetic. A good 5W-20 is fine if you change it often. Note: it is a myth that all dealers use the same brand 5W-20.

When you change the oil in an RX-8 ( Series I and II have the same model of engine but there are many differences) you will leave more than half in the engine, oil coolers, lines, etc. So if you do not change often (every 3,000 or so) then the quality of the oil in your car is **** because you are mixing new oil with used and abused (depending on how long between changes) engine oil.

A better, higher viscosity oil will stand up to abuse better than cheaper, lower quality oil. But again, a lot of that is opinion, preference, etc. The only real way is to test your oil in your car a few times and see how it does. And even then testing can be questionable as well.

But, IMO, if you buy a good fully synthetic 10W30 or 5W-30 and change it every 3,000 or less, then your engine will love you in Texas. That said, there are very good dino oils such as Castrol GTX (my second motor lasted almost 80,000 on it) and I run Shell Rotella 5W-40 in my engine but I test my oil so I know how it is standing up.

If I was you however I would run what is recommended. Although the Series II engine is much improved and does not seem to suffer from premature failures I would not risk a warranty denial because you used a different oil. yes you can argue that the oil is only RECOMMENDED in the owners manual and not specifically required but do you really wanna hassle with that?

WTBRotary!

iTrader: (6)

The dealer has to prove without a probable doubt that synthetic messed up your engine, plus there is nowhere in the manual that says to not use synthetic... I could go on forever but you need to read the countless oil threads on this forum...

9krpmrx8

iTrader: (46)

Yeah, you would have a good argument with the dealer and Mazda USA but in the end if they deny it, your the one who is screwed while trying to prove your case. legally they would have to prove it in court but that would be a long, long time from the time your engine failed. Some dealers are hard core and they vary greatly in how they handle things. You have to be realistic, most people could not make the argument successfully.

Either way, if you use synthetic or dino oil, you need receipts now to prove maintenance and in some recent cases people have been denied who did oil changes themselves. So, if the dealer ever asks, you use 5W-20 Dino oil and if you are going to do the changes yourself be meticulous with how you document that.

I was lucky to have access to receipts for my third engine at 96,000 because I had always done oil changes myself but the last three or four oil changes before it failed were done at a shop because I was going through a divorce and did not have a garage. Had I had access to a garage I would have done them myself and they would have denied it.

WTBRotary!

iTrader: (6)

Then you need to take it to a different dealer, because your dealer sounds like it sucks...

9krpmrx8

iTrader: (46)

My dealer has been okay (replaced two engines) but on this last one at 96,000 there were totally different and way more difficult. The first time (at 22,000) they didn't ask me for **** to prove oil changes, etc. and paid for the rental no problem but the second time I had to jump through hoops and my extended warranty picked up the rental, etc..

You and I are lucky to have a variety of dealers to choose from but many do not have that luxury. I don't understand why they are so tough now because they get paid to do the work but there must be a reason. Mazda USA must be cracking down.

Rudolph

Here in Europe (the Netherlands; with a total of only 350 Rexes all over the country) my official Mazda-dealer (servicing a couple of Rexes) fills with fully synthetic 5w30 oil from BP (also during guaranteeperiod of 3 years); he is not the only one; generally most Mazda-dealers fill all their Mazda-types with oil from one drum; fully synthetic 5W30. {Since short I change oil myself and use fully synthetic 0W40 / lowSAPS (seems better for longer cat-life and lower ashresidu's in combustion chamber) / ACEA A3, B3, C3; API SM/CF from ARAL(BP)}.
http://www.oelshop24.de/products/0/0...nic-0W-40.html
Furthermore I premix; started at 5000 miles from new (Series I).
Attached: picture from a trailing plug from the 1st and a leading plug from the 2nd rotor after 5000 miles of premix

Best regards, Ruud

9krpmrx8

iTrader: (46)

Do I have to post this again? Genuine Mazda part.

SpacerX

I recommend the running gun battle that is the Cumulative Synthetic Oil thread in the Series 1 Tech forum

https://www.rx8club.com/series-i-tech-garage-22/cumulative-synthetic-oil-discussion-52856/

But I'll briefly summarize some points here:

1. The term "synthetic" has become purely a MARKETING TERM, except for purely PAO-based (Type IV) motor oils. Most oils in the 5W/30 and ALL oils in the 5W/20 range could easily be called synthetic or synthetic blends (Type II-III or Type III), due to all the additive packages required to meet modern standards.
2. Only the "boutique" oils -- like Royal Purple, Amsoil, and Redline -- tend to have PAO-bases; and even these are a far cry from synthetics of old, having gone through several evolutions of additive packages, in keeping with modern standards -- by all reports they work very well with the Renesis engines.
3. Use of the standards -- set forth in your owner's manual, like SAE, API, and ILSAC standards -- are the ONLY specs at issue, NOT whether the label says synthetic or not. Furthermore, Mazda recommends 5W/30 in other markets, there should be no issue with your warranty if you use 5W30.
4. Several RX8 owners have achieved outstanding results with a range of oil and lubrication strategies. When I owned mine a few years back, I used Motorcraft 5W/20 but did not premix. I suspect if I purchase another RX8, I'll use 5W20 in the winter, phase-in 5W/30 for Summer, and use a premix, even though it appears the Series 2 has a much-improved oil metering system. If I were to run track time, I'd use a heavier oil, like -40 or -50.
5. The importance of a hig-quality filter CANNOT be overstated. My research indicated the OE filter was always a good choice, but the Purolator Pure One filter had the best filtration media performance and overall density of filtering area.

Anyway, the most important things to keep in mind: change your oil more often than the 5k- or 7.5k-mile recommendation; use good oil that meets the standards in the owner's manual; & use a good filter.

Ciao!

jasonrxeight

put in some 5w20 GTX and call it a day.
Ive seen engines only lasted 40k miles with extensive care and engine lasted 80k miles with almost no attention at all.
rotary engines are very hard to tell when to go. good thing you have a very long warranty.
so just enjoy the car.

Never L8

iTrader: (5)

+1! I've read countless posts on this, looking for a final place to settle on my oil. After reading for who-knows how many hours, the advice jasonrxeight just rendered is truly some of the best out there. Trust me. Retain your sanity. These engines have failed with even the most meticulous of care. Just change your oil and filter every 3000 miles. I will probably start pre-mixing when I get my new engine, but other than that, I'm not changing a thing.

terch1

iTrader: (2)

Amen. I use the Castrol GTX in all my cars. Can't beat it!!!!

painoracing

I live in Puerto Rico were definetly is hot all year-round. I discused with Racing Beat and local mod experts in rotary engines and they recommend and use full synthetic 5w-20. They have seen power loss with 5W-30. My car is a daily driver, stock engine (RB airbox, RB flash and RB cat-back) and sporadically used for autocross.

My dealer, for the first 3 years, used Mazda North America 5w-20 oil. The last time they used 5w-30 without telling me. But I will change to Royal Purple Syntehtic.

The explanation my dealer gave about the synthetic oil is that the type of oil is not the issue, that they recommend regular oil because people tend not to change oil frequently when they have synthetic. They guarantee me that I could use synthetic oil but I had to change it as recommended by manufacturer (Mazda)and I would not have problems with warranty.

My research in the past few years tells me there is no problem with synthetic in the newer RX8's.

Just to share...

Chibana

I've been using Royal Purple 5W-30 oil from the beginning (bought my car March 18th, 2009), and I have the dealer do the oil change. They were fine with the oil weight and brand, and Royal Purple states explicitly on their website that their oil is not only safe for rotary engines, but a good choice of oil for them. Racing Beat and other rotary shops also recommend Royal Purple, which is the main reason I decided to use it.

9krpmrx8

iTrader: (46)

Royal Purple Royal Schmurpal. If they get in trouble for lying their ads what else do you think they are lying about? Not that it is not decent ( I have seen UOA's that were great) but it's not the holy grail of freakin' oil. Most name brands oils are fine if you change your oil regularly.

Albmw

hot all year ...? 0w40's are great for Chicago, but Puerto Rico?? ...when your engine is warmed up, I don't think it matters where you live, engine temperatures are the same. Difficult to sell synthetic oil from a environmental perspective, so it becomes a "performance" oil...we can get more horny from that pitch and can buy more expensive pointless oil (unless of course you are a tree hugger)..

WTBRotary!

iTrader: (6)

Try out Royal Purples new Oil Filter, its pretty Badass, ive read about it on their website and researched it. at $15 per filter its not cheap but the differences compared to OEM and others seem to make it worth it.



Dont hate Royal Purple, just because your not on the Purple KOOL-AID doesnt mean you have to be a hater...

Beefy98

page 8-12..."Do NOT use synthetic or semi-synthetic oil in the engine, otherwise starting performance could worsen"