I bought my 8 about five weeks ago, I did some research of course before I bought and I did contact one of my sons who worked for Mazda and asked for an unbiased opinion.
He told me to accept the fact that they are very heavy on fuel and that 94 octane was the best fuel to use and he recommended Chevron only, ( not too sure why ). Oil consumption was something to keep a close eye on and suggested that every third fill I should check the oil level.
He told me that when he worked for Mazda as far as reliability was concerned that although the RX8 has certain issues in the past they appear to be very reliable now. He praised the performance and design and the interior finish and prior to me buying I should take whatever time it takes to find a top of the line GT 8 with low mileage and if the basic standard warranty had expired to purchase a bumper to bumper extended warranty for a couple of grand it was money well spent in his opinion.
I did find a beautiful 8 locally, a metalic blue, a GT model with every option and it really is a fabulous automobile indeed. Of course it is heavy on gas but that's the price you pay I have about 2500 kilometers on it since I bought it, I check the oil level on a regular basis but the level still does not indicate that I should add,,,,,,and the oil still is very clean,,,,so far so good I guess.

 

91 octane is probably your best bet in a NA rotary, nothing wrong with 94, it's just used less and more $/ any major gas retailer that goes through alot to ensure cleaner tanks and fresher gas is best/ some folks have a favorite gas station and that's ok, at least it is being consistant.

 

give us some more info:

year, auto/manual, miles?

how you drive it? easy or rough? are you redline it regularly?


2500km without need to add oil that is not normal.

you also try to change oil every 5000km
and use 5w30 or 10w40
mineral or synthetic is your choice.

i use 10w40 semisynthetic

 

I don't want to start a big oil war or anything, but I thought you weren't supposed to use any synthetic oil at all.

 

FTFY

If you drove 2500km and you haven't consumed any oil I'd consider starting to premix. Not sure why, but some OMPs seem to flow less than others. Mine drinks like a pig... by 2500km there's at least half a quart gone.

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

 

thats why i said "IS YOUR CHOICE"

Mazda does not recommended it and is in the 2009 rx8 owners manual.

please <<SEARCH>> and make your own assuptions.

 

Oil consumption depends on your driving style. If your not pushing the car, it barely consumes oil. If your WOTing or high RPM all the time, then it will consume more oil. Basically load dependent.

thewird

 

from what i've read here, the rx-8 does not consume oil like the rx-7. it still uses some, but it's only an oil piggie during the first 5k/10k miles during breakin.

 

I don't seem to use much oil in my series I between my 3k mile changes, and this even with MSP16 and CobbAP-MM upped injection rates. Spirited driving most of the time as well.

 

True, however if you are constantly driving in the lower half of the RPM range you would be opening yourself up to other problems.

There's a thread somewhere about this situation and the result was that the third intake port had so much carbon on it that it wouldn't open up anymore, requiring a rebuild.

By 5000km I have usually used up a full quart of top offs and the oil level is back to the MIN line [at least that's what it was before the OMP bypass... now I just keep the external tank full]. I think I am at the higher end of the oil consumption though; haven't met anyone who consumes as much as I do.

 

That's why there is the saying, "a redline a day, keeps the mechanic away". It cycles all the ports and at 5,500 RPM oil injection goes up significantly at WOT.

I usually hit the buzzer in 2-3 gears on the offramp when I'm going home.

thewird

 

Take it to a track, than see how much oil you burn. Last time at Shannonville a quart and a half.
But that was beating the crap out of it!

 

A redline a day does not keep the mechanic away (I hate that stupid saying).

I love my 8 but it is far from "very reliable". Personally I would stay away from a used 04-08 unless you don't plan on keeping it for more than 50k or unless (like me) you love to wrench. You can get a 09' for very cheap nowadays. The 09's have yet to be proven (most 09's are barely at the 10k or less mark) but it does look as if they fixed the short comings of the previous gen Renesis (added thrid oil injector, revised OMP system, more oil pressure, etc, etc.).

The failure rate seems to be about 25% for the 04-08's and while many believed the problems to be limited to the 04-05's, we are now seeing more and more 06's with failed engines so I think it's safe to say, as mileage goes up the 06,07, and 08's will suffer similar problems.

On a hard track day I can consume a quart of oil easy.

 

^ At a minimum it keeps the valves in use and heats it up a little.

thewird

 

Yes, you are right. I just hate it when people act like its a savior for this motor when its not. Each of my engines in 100,000 miles of use were meticulously maintained and redlined daily and it made no difference, they still lost compression. On this third motor I am taking a different approach but many won't go to the lengths I have to maintain their 8's and there is a possibility that it may all be for nothing, only time will tell.

 

Except we already know the 6-speed gearbox has major issue in the 09+, so you can't win either way. Who would have thought the 04-08 gearbox is actually the reliable one.

Just do the premix + fuel cleaner thing with every fill-up. I use RedLine 2-stroke oil and SI-1 fuel cleaner. Do they do anything? I have no idea, but it probably can't hurt.

 

so then, i have an 06 and if the engine fails i'm going to get an 09 block put in, since it has improved oiling :D

 

Not a practical solution. Too many other related changes. It's not "plug n play"...

 

Oh hang on a minute buddy, perhaps when it comes to pricing and reliability down where you live it's way different but I was the original poster of this thread and I definately argue on two of your points.
To quote you, " You can get a 09' for very cheap now " maybe down there but not up here, they have a nice red one at the local dealership here, it's an 09 and priced at $ 54,000.00 most new 09's at Mazda dealerships are in the $ 45k. range and up.
Next point, I don't know where you are getting your information from regarding ALL these engine failures in RX8's. I have a friend who works as a Mazda technician for one of the largest Mazda dealerships in B.C. I ran your posting by him and to be honest with you he said you were " talking bloody nonsense " his words pal not mine. He told me that in the past three and a half years he has had two 06 RX8's in the shop with failed engines and BOTH were proven to be caused by poor ( or lack of ) owner maintenance.
His opinion and the opinion of other Mazda certified technicians is that if the Mazda regular maintenance is performed according to the owners manual then the ROTARY GENESIS ENGINE WILL BE AS RELIABLE AS ANY PISTON ENGINE INSTALLED IN ANY MOTOR CAR.
He also mentioned that they had a 03 RX8 in the shop last week with 219 thousand kilometers on it, they were performing regular maintenance. The car was in excellent condition mechanically and otherwise, well looked after and running strong. He also mentioned when it came to engine failures in Mazda vehicles there is no more incidents of that in RX8's than there is in, for example Mazda 3's or 6's.
I respect your opinion as I hope you would respect mine, but posts with innacurate information regarding ALL these engine failures really will deter potential buyers from purchasing one of the nicest sport cars on the roads today,,,,,,,,have a nice day.

 

I have used 2 quarts in just over 4000km. Some hard driving and I premix 5oz per tank. I have a 2004 with a reman with about (45,000km) on the motor. I'm running 10w40 Royal Purple. Is this unusual or is it really dependent in your driving style? Or does it consume more as the oil breaks down?

 

I have some oil consumption stats for you if you are interested.
I live in Dundas Ontario (beside Hamilton) and have a 2008 40AE (6MT) that I bought used (37000km) in Dec 2011 and have used it year-round since (now at 77000). I'm using non-synthetic Castrol GTX 5W20 as recommended by Mazda for my area/weather zone. I thought synthetic oil was not recommended due to the risk of fouling the iridium spark plugs, however I'm not sure what oil additives will do either. I keep detailed gas, oil, mtce records in Excel and trend both gas and oil consumption. I was car-pool commuting on rural highways (80km/hr limit) from Jan to Dec 2012 and put on 28000 km by averaging 76km/day but then retired in Jan 2013 and since have added 12000km by averaging 45 km/day (mainly short distance city driving since). Not surprising, may oil consumption increased, but I was able to quantify the increase. My average oil consumption went from 0.3 L/1000km (commuting) to 0.5 L/1000km (short distance city). I've also noted while I did not seem to have any seasonal oil consumption variations while commuting, there has been a definite oil consumption increase in city winter (0.6L/1000km) vs city summer (0.4L/1000km) driving (not surprising really as a significant portion of my of my city winter driving was done with a cold engine i.e. high stress). So with a swing of 0.3 to 0.6 L/1000km, if you asked me what my oil consumption is I guess I would have to say "it depends what I'm doing with the car". If you can, warm-up your engine in the winter before starting out, and change your oil more frequently than the 8k recommendation from Mazda if you drive mainly short distance city driving. I'm changing my oil every 4k since retiring (doesn't cost much). I think its a good idea to trend your oil consumption (Excel will let you easily make a trend graph) so you can diagnose any changes (+ or -). Hope this helps.