...that have been beaten to death. And yes, I have searched endlessly here and elsewhere, only to find conflicting info.

1) My manual for my new '05 RX-8 states to use non-synthetic SAE 5W-20 motor oil. I live in Michigan, with many 90 degree + (fahrenheit) summers, and 10 degree - (fahreinheit) winters.

Is this a year round recommendation that should be followed? Should I use 5W-20 even in the hottest weather? And is it definitely not good to use synthethic motor oil (Mobil 1 states it is not intended for use in Mazda Rotary Engines)?

2) My manual states that 91 Octane fuel should be used. If mid-grade (89 octane is used), and there are no compression/pinging/ECU problems, will there be any warranty issues in the event something breaks, and even if something does not break, will there be any material impact on the long term wear of the engine?

Before anyone tears me a new one for asking these questions, do a search, and if you can honestly tell me there are clean cut answers to be found. There are not.

Thanks in advance. I'm loving the 8 so far.

 

Very few things in life have definitive answers.
Based on reading posts here since Feb 2004 here are two definitive statements
1, Not one thread or post titled " Synthetic oil ruined my 8 "
2, Not one thread or post titled " Mazda voided my warranty because I used 87 octane "

Now for personal experience.
1, I change my oil every 3,500 why use Synthetic ?? New Jersey gets hot / cold also, 5-20 year round for me so far.
2, I use 89 Octane 98% of the time. I have 46,000 miles and my 8 runs fine. Use what ever grade gas that will not ping.

 

in the manual, it states for the united states, to use 5w20 year round, according to the little graphic that is included for the oil recommendations.

also, in the manual, for octane, it states that for best performance, use premium fuel, but lower octane fuel may be used, but you will most likely see a decrease in performance.

 

Right.

I am in agreement (from my own theorizing) on the oil issue. I'm sticking with Castrol GTX 5W-20 for now, for when oil needs to be added.

I'm less certain about deviating from the octane recommendation.

As an attorney, I know that deviation from manual recommendations can be one of the first excuses seized upon a company to avoid having to honor said warranty.

I had a case a while ago for a client that literally had a fleet of Toyotas in his business. 4 wheel drive Toyota 4-Runners and Camrys with 3 liter engines were developing sludge and seizing. Toyota was trying to find any excuse whatsoever, and using a fine tooth comb in doing so, to try and avoid paying warranty claims.

 

I honestly wouldn't use synthetic oil. I always ran Quaker State or Castrol and my 7's lasted forever. The problem with synthetic oil is that it doesn't actually mix and burn like petrol based oils. Remember, rotary engines operate on a two stroke principle. Because you cannot get a flow of oil to the apex seals, you have to mix oil (homogeneuously) with the gas. It also burns up and flows out the exhaust. If you use synthetic oils, the polymer chains don't mix well (heterogeneously) with gas and don't burn correctly. Remember, engine oil and gas come from the same exact barrel of oil. Through fractional distallation, the crude oils is seperated into motor oils and fuels. In addition to shorter engine life, I'd expect the cat's to foul up.

 

You want definitive answers to probably the 2 most debated topics in the last 2 years?? Good luck :D .

Fwiw, I've used 5W30 for the last 42000 miles and mostly 89 octane. But then I've had zero warranty work done other than recalls, and had a good service department. So I can't say if this would normally be a warranty issue.

 

read rotarygod's take on synthetic

https://www.rx8club.com/series-i-tech-garage-22/rotarygods-rotary-oil-tech-blog-69805/

 

I'd have to disagree still that synthetic is a good choice for long term rotary survival. From what I have read, it will also void your warranty:

"Also, as synthetic oil is not supposed to be used with rotary engines, the warranty on Mazda cars with such engines will be invalidated if this kind of oil is used."

you can find it here:

http://www.autoworld.com.my/EMZine/R...=RT.ATC.CAR.PV

I also did a search and it's a reaccuring theme. Use synthetic and loose the warranty. Mazda's FAQ ont heir site doesn't say you should not use synthetic but rather says only use what's recommended in the manual.

 

I am not looking to pick a fight with anyone, including rotarygod, but the advice to "go ahead and use synthetic oil, despite the fact that warranty cautions against it, and if anything happens, deny that you used synthetic oil," is just plain bad.

Using synthetic oil is giving Mazda a gift of an excuse to void your warranty if something nasty happens to your engine, whether doing so is the right thing to claim and/or do.

If they can find an engineer who will claim that the synthetic oil led to the mechanical problem, while maintaining a straight face, whether it did or didn't, they just might.

Why chance it?

 

My Masda Dealership in Hamilton NJ stated to me that they use a 5W-20 Blend. It actually has a little synthetic to it. They swear that is what they use. They buy it in bulk from Valvoline. The only 5w20 that I can find is Mobile7500. That is what I use.

As far as the gas ... so long as you are not pinging you can drop to midgrade.

 

Heres an even better one:

Fallacy: Using synthetic oil will void a new-car warranty.
Fact: With the exception of the Mazda rotary engine vehicle, which does not recommend using any synthetic motor oils, Mobil 1 will not void new-car warranties.

Guess where this comes from:

http://www.exxonmobil.com/Corporate/...r_050104_1.asp

If you're gonna trust Mazda enginnering enough to pay 30k for one of their cars, then you shouldn't be second guessing them about the oil they recommend. That's my view anyways.

 

you are correct. use whats in the manual. according to the manual, mazda states to use oil with the api or ilsac labels on the packaging. they also state to use, for temp's between -20 F (-30 C) to 120 F (50 C), to use 5w20 oil. they also state that the use of energy conserving oils is recommended.

they do not say anything about using mineral or synthetic oils.

see pic below. i have altered the coloring of the pertinent points here.



now here is are scans of the front and back of the oil that i use, royal purple full synthetic, 5w20. notice how the ilsac label is present on the front, and the sl label is present on the back, and that the grade of the oil is 5w20, as per specified in the owners manual.




so, if i understand what you are saying, that even though i am following mazda's recommendations to the letter, according to the owners manual, my warranty is void????

 

For the peace of mind, I would stick to non-synthetic oil since there burn off cleanly. As for the engine viscosity I would switch to 20-50W if your area is about 37+ degrees celcius. However you have winter there so I think its not entirely suitable to use the above mentioned oil viscosity. Fuel wise I will strongly advise to use better fuel for the car, you don't wanna give the dealer a chance to refuse warranty. Plus you not hearing pinging doesn't mean its not happening, the important thing is the MON of the fuel not just the RON, its the MON rating that's really preventing the pinging. Two fuel grade can be different in RON but same in MON.

 

That's a good post, and I'm serious. I appreciate the jpg's. It helped to follow where you were leading.

Basically, what I'm saying is that anything an owner does that is not in strict conformance with the manual is an open door for Mazda, or any other manufacturer, to deny a warranty claim (whether the ethically right thing to do, or not).

Since the manual states synthetic oil shouldn't be used, I view that as a classic invite for a warranty claim dispute with Mazda in the event that there is a mechanical breakdown.

This, despite the fact that Royal Purple, Mobile 1, or some other synthetic oil may truly be superior to petroleum based engine oil. The rub is not the truth; the rub is what is done versus what the manual says.

As I've stated, I had a rather large (by consumer standards) case against Toyota in the past, whereby a client had numerous engines (all 3.0 liter) sieze due to sludge build up.

Toyota fought tooth and nail to deny the claim under their warranty. They got into the kind of minutia that would shock anyone here (brand of motor oil, weight, temperature of climate, service shops that did the work, driving habits, etc.)

As it ultimately turned out, that sludge build up problem was a big issue for Toyota, and one that they faced a massive class-action lawsuit over (they were sued by the AG of California, too). The evidence points (to this day) to the fact that those engines had design defects whereby the pistol cylinder tolerance and seal was far too tight.

Sticking to the manual raises the bar for Mazda to try and defeat a warranty claim. Deviating from the manual lowers the bar.

The truth as to what caused the failure, and whether it should rightfully be covered by the manufacturer is too often a factual tidbit that gets lost inthe forest of legalese.

 

any possible way you can post pics or page numbers where it states in the manual, or elsewhere officially affiliated with mazda, ie mazdas website, owners manual, official mazda addendums, where it states this?

 

lurch - I'm going to go check my manual right now (which I should have done to begin with), to try and find such language.

You may be right. It may not be silent on the issue of synthetic oil.

I assumed too much for my own good (maybe) because of the fact that Mobil disclaims responsibility of voiding the warranty on Mazda Rotary Engines (which leads me to certain assumptions).

I'll follow up.

 

To answer question #2:

Page 4-2 of the owners manual says:

You may use a regular unleaded fuel with Octane Rating from 87 to 90 (91 to 95RON) but this will slightly reduce performance.

To answer question #1 and lurch519's excellent point in the manual:

Page 8-7 refers to the additonal warranty information booklet.

On page 11 of that booklet it says that using improper oil will void the warranty.

While the synthetic lubricant may have the quality standards that Mazda says must be on the bottle it doesn't say to use synthetic lubricant directly. If you still don't believe me here's another:

Myth #3

Using synthetic motor oil will void a manufacturer's warranty.

Fact
As long as the synthetic product meets the viscosity and performance requirements outlined in the vehicle’s owner’s manual, using synthetic oil will not interfere with the warranty coverage. However, one exception would be the rotary (Wankel) engine used in certain Mazda vehicles, which recommend against the use of synthetic oil in that particular engine.

Came from here:

http://www.quakerstate.com/pages/carcare/whattoknow.asp

The fact that synthetic oils are a seperate classification of lubricant and not listed in the manual implies not to use them.

The warranty actually does not need to spell it out by brand and type in the manual for it to be binding. Mazda simply says that all service should be provided by Mazda or a qualified techinician. Therefore, the Mazda dealer or qualified service center would be properly trained to tell you not the use the full synthetic oils. Of course, you could always pay for the work then sue Amsoil for the cost fo repair.

 

Okay - just checked manual on the oil issue. Page 8-12 of owner's manual.

Only two requirements:

1) SAE 5W-20.

2) Quality designation SL or ILSAC muste be on the label.

Based on that, Mazda would have a tough time defeating a warranty claim based on the use of partially synthetic or completely synthetic engine oil, IMO.

Hmmm....contemplating synthetic again.

 

On the oil issue, it looks more as if the oil manufacturer is playing CYA, rather than Mazda.

If something untoward happened, Mobil could deny coverage on the basis it warned against the use of its product in the rotary engine.

 

But doesn't that scare anyone that all the manufacturers of these oils say don't use it because it will void your warranty?

In reality, there are only 2 ways to solve the issue. First, we could tear apart some engines and measure some wear on the seals. Or, second, we can send an email to Mazda and ask for an official clarification on the warranty/synthetic issue. Then we would know.

 

More on the subject of dealer service and Mazda's stance:

We recommend that only a Mazda dealer services your vehicle, as our technicians are Mazda trained with the latest technical information to ensure optimum performance of your vehicle. Mazda dealers are equipped with WDS ( World Diagnostic System) which allows them to check your vehicle management systems and computers for correct operation. The WDS also allows for the latest system updates (where available) to be programmed into your vehicle computer systems to enhance the operations in various areas such as engine and transmission. Only Mazda dealers are able to do this. Also, it is well recognized within the motor industry that vehicles with full franchise servicing, generally attract higher resale values when the time comes to trade.
As you are aware, Mazda New Vehicle Warranty is not conditional to having your vehicle serviced by a Mazda dealer. However, should you experience any difficulty with your vehicle during the warranty period and the cause is found to be a result of incorrect, or lack of scheduled maintenance servicing, then Mazda will not be responsible for any damage that may occur.


Does Mazda have a recommended Oil for use in it's vehicles?

Mazda recommends the use of Mazda's Full Synthetic, "Premium Motor Oil" API SL 5W-40 Motor Oil in all it's Petrol and Diesel Engine vehicles and Mazda "Rotary API SL 5W-30" oil for all Rotary engine vehicles. This oil is also available in convenient 1ltr quantities for use when topping-up the oil in Rotary vehicles.
Mazda also has available genuine "Long Life Coolant" for use in the Engine's Cooling System.

came from:

http://www.mazda.com.au/articleZone....icleZoneID=115

 

you are right, the manual doesnt need to nor does spell out by brand for what oil to use. but in the warranty book, it states

the manual does not specifically state to use mineral base oil, nor does it specifically state not to use synthetic oil. to me, as long as the oil i use meets the specifications set forth in the owners manual, that it is 5w20, and that it meets the SL or ILSAC specifications, and that i follow recommended service intervals, then there will be no issue as to warranty.

i am not trying to start any arguments, i am not trying to start any wars. i am not saying that anyone should use synthetics, i am not saying that synthetics are better than mineral based oils (though most everything i have seen and read seems to indicate exactly this), i am not saying synthetics are the best for the rotary engine.

what i am saying, is that after reviewing the owners manual, and the warranty book, that mazda does not specifically warn, prohibit, not recommend, etc against the use of synthetic motor oil.

i am also saying, that after doing research, i have made an educated choice, and have chosen to use full synthetic as my motor oil of choice.

i am sure that everyone else here will make their own choices in this matter.

 

Now, THAT, is bizarre.

Mobil 1 disclaims warranty coverage specifically for the rotary engine, yet Mazda endorses the use of a 100% synthetic oil.

This is a paradox, no?

I am simply stunned.

Lurch - I think you've been quite the gentleman in getting your point across. Which was correct, as going by the stock manual, by the way.

 

thank you rotorocket.

as to the bizzareness of that statement, they endorse synthetic for all petrol and diesel engines, but the recommend a "rotary oil" for all rotary engines. the really weird thing about this statement is that a rotary engine, is a petrol engine. go figure, all the time, effort, and money spent on lawyers, engineers, and proofreaders by large corporations, and yet they release an ambiguous statement like that.

 

Just so happen both of the questions were answered in the RX-8 DVD, you can download the video someone uploaded

https://www.rx8club.com/rx-8-discussion-3/rx-8-dvd-mail-today-73215/page2/

But to summarize what was said in the video: (pretty much what were already posted in the thread)

"although Mazda rotary engine's oil seal is compatible with synthetic oil, the long term effects are unknown, therefore Mazda does not recommand using synthetic engine oil"

"91+ octane for maximum performance, 87-90 octane may a cause a reduction in performance, Less than 87 octane may cause knocking and engine damage"