How to care for RX-8 (rotary)? Proper oil?

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I owned a 2004 RX8. The car is a good looking, clever design that has good weight distribution and excellent handling. I always thought the platform was a good fit for a flat 4 engine. The Renesis engine has seal lubrication issues. Oil injection is problematic from an EPA perspective, so Mazda is trying to inject the minimum amount of oil at the RPM ranges that EPA looks at. The EPA allows more oil injection at higher RPM levels, which is one reason why redlining the Renesis is beneficial. Redlining also helps to reduce the deposits at the exhaust port. In the RX7, the apex seals passed the ports. In the Renesis, the side seals pass the ports, so the side seals are the usual failure. Premixing TCWIII or other 2-stroke lube helps greatly. My motor responded well to premix, immediately running smother and revving easier. I just started it too late to save the seals. The RX8 boards have a never ending discussion about which oil is better. There is no magic solution to Renesis engine longevity. If you purchase one, set aside funds for a motor rebuild and enjoy the ride!
 
Originally Posted By: Dominic
IIRC the rotary motors have an oil injector and oil consumption is actually a part of their operation. Enjoy the motor and just check the oil and add as needed.

I wouldn't change grade, but perhaps use a good quality recycled oil like Valvoline Nextgen Maxlife. At least then you're consuming a recycled oil, which is slightly more eco-friendly - and you get maxlife benefits to keep the engine in good shape.

I'll be interested in what some of the more knowledgeable people in this thread suggest to you that are RX8 owners.



Fully agree with this post. Old roommate of mine had an RX-8 and he basically just bought whatever oil was on sale. No noticeable difference among any of them, and it did drink a decent amount of oil (normal and actually beneficial).
 
Originally Posted By: Clevy
I remember a guy with an RX-8 with some total quarts he wanted to trade for castrol gtx,quart per quart.
He said something about it leaving no deposits behind on the apex seals when it gets inevitably consumed.
That tells me a lot. If a guy is ready to trade really good syn for vanilla castrol that's what I'd be using.
I saw the thread he last year iirc.


That was me. I ended up using the Total in our CX5 which appears to like it. I was looking at deposits on the plugs and tail pipes and while to Total was much better than all the Mobil 1 line with the exception of the 0w40 it still left a more tenacious residue than GTX or any of the Valvoline products I tried. Interestingly GTX 10w40 does leave a little less residue than 10w30, 5w30, or 5w20 in my use.

OP, oil is but a small part of the RX8 longevity and one with many opinions that often seem to work. Another more crucial part IMO is the ignition system maintenance. I personally change my plugs, wires, and coils every 20K miles and the community seems to be on par with this. This version of the rotary eats plugs and coils and bad health here will destroy the CAT along with other parts of the engine in shorter order.
 
I had a 2010 RX-8 for a little less than an year. Bought it brand new and sold it with less than 12k miles on it. It was a fun little car but the fuel mileage wasn't working for me anymore. I always ran castroil in mine. It ate about a half quart every 1k...sometimes a little less, sometimes a little more. You also have to change the spark plugs very often on the car, which can be expensive if you don't do it yourself. Also the oil change in general is a PITA as the car is very low and putting it on ramps didn't help much. Check out the RX-8 forum and read up.

FWIW a guy I work with has a 04 RX-8 and he NEVER checks his oil level, changes it every 3-5k, never done anything else maintance wise on the car it has over 100k and runs great....or so he says anyway.
 
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Originally Posted By: blackman777
I see the 2009 engine was redesigned with additional oil injection ports.
Maybe that's the model I should choose (for longevity).



yes get a 2009+ i had and R3 for a while. Sexy car, and i ran MS5K 5w20 in it. make sure you run the mazda filter if you get and 09+ the oil pump puts out way more pressure than the 04-08's also be prepared to rev the snot out of the car. take it to the beep multiple times per drive (after its warm)

They are one of the best handling cars ever IMO. my R3 was so so good in the twistie's. The car is not fast tho. It runs decent if you keep it between 7.5-9k and the temp is cool. In 90 degree heat with the A/C on a corolla will outrun it. no joke.

Mine was very reliable in the time i owned it. I liked the car, but it had exhaust and was really loud, and a new stock system was like $1500. so i just decided to trade it for a vette. the vette was my dream car.

The Rx8 is also annoying to pass in. You literally have to downshift from 6th to 3rd at 55mph just to have passing power. its not light on its feet as it is gutless. you will learn very quick to keep the revs high or ride a gear or 2 low if you plan to accelerate in traffic.

They are great cars, but rough around the edges. they remind me of a 125 dirt bike. very peaky, kinda weak and you must wring them out often or it feels like it loads up. i seriously used to joke that it was my 2 stroke car, as i would put in a few onces of 2 cycle oil in every tank of fuel, which was filled often. i used to get 19.6mpg no matter how i drove it. For comparison i can drive my vette all city and get in it every once in a while and get 23mpg and constantly get 31.9mpg highway.

I will warn you about the biggest problem with the RX8, however. It is very very hard to sell. very few people want one. most people are scared to buy one because of the early models. I sat trying to sell mine for a few months and for a good price. I traded it in and i received what i had been trying to sell it for for 3 months. One dealer where my fathers friend is the owner refused to make me a trade in offer because he said he cant sell an RX8. he said he had two in the past. he bought them at and auction the same day and they were lower mileage cars. he said he had both of them for 11 months and couldn't move them. he took them back to the auction and lost $200 on them just to get rid of them so he could buy something he could move.

if you buy one plan to keep it or give it away when you plan to sell it.
 
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Originally Posted By: CATERHAM
Originally Posted By: jrustles


I'm talkin' bout Pennzoil Ultra 10w30, that should burn the absolute cleanest of anything you could buy, and cleaner burning means less deposits to form around the seals, like a conventional oil will do. Combined with 2T premixed fuel, or conversion to dedicated 2T oil injection and that setup should have the rotary bulletproofed and ready for a long life.

PU is a relatively clean burning oil but it certainly isn't the cleanest in terms of deposits in the TEOST 33 (ASTM D6335) test.
The cleanest API oil I know of is Castrol Edge 5W-30.


Wrong test in this case. TEOST 33C is an aged oil hot tube turbocharger deposit test. The Renesis needs oil that burns cleanly in the combustion chamber.

If you're picking the lowest risk oil get the Mazda Rotary 0w30 or the Idemitsu Rotary oil. http://www.idemitsu-usa.com/h/35/products.html

I'm no great expert on roataries, but I know the "no synthetic for the rotary" advice is a trope. There may be some reason not to use PAO and Ester, but Group III is good. Both the Idemitsu and Mazda rotary oils are synthetic.

If you want something OTS, Pennzoil Ultra 10w30 would be my choice. Pennzoil has stated that they designed it with clean combustion in mind.

You won't get the best advice here, poke around the rotary forums or call Mazdatrix or Tri-Point engineering.
 
Originally Posted By: 901Memphis
They have a low oil light, how could someone drive it intentionally with that light on?

People who don't read the owner's manual do this. I often replaced many oil level and oil pressure sensors, and the owner of the car actually drove to a repair shop to diagnose the warning light. In many cases, the sensor only leaked a bit of oil, or failed in the circuit closed position. I have to wonder how many other people decided to push their car further, and have an oil related disaster, and that is the reason I never encounter them.

Also, there is another potential problem with the low oil level warning. How can you be sure it is accurate?

In any case, if I encounter someone that has major problems with their RX-8, and they don't need 4 seats, I recommend they find a good used Honda S2000. It is another RWD car with great balance and cornering, and the engine encourages you to rev it up hard.
 
Originally Posted By: OMCWankel
Premixing TCWIII or other 2-stroke lube helps greatly. My motor responded well to premix, immediately running smother and revving easier.
Ahhhh that's what people mean when they say, "Maintain it like a two-stroke engine."
smile.gif


On youtube there's an S2000 vs. FRS vs. RX-8 head-to-head video. Both of the testers rated the S2000 above the other two cars. Honda really should revive that car rather than waste time on the hybrid CRZ that is powerlow.

I think I will wait for the RX-9.
Or maybe just skip rotaries entirely. I like collecting cars with nonstandard power plants (hybrid, diesel, electric, rotary) but $15,000 is a lot of cash to spend on a car with only 100K engine lifespan.
smile.gif
 
Originally Posted By: blackman777
I am shopping for a Mazda RX-8 but reading a lot of horror stories about the rotary engine:
- never use synthetic oil
- buy lots of oil because the engine consumes a quart every 1000-2000 miles
- the seals often "blow out" and need replaced

Anybody have recommendations on what proper Oil to use in this finicky engine? The manual says 5w-20 but I'm thinking a thick 5w-40 might be better to reduce consumption? (Not Mobil 1 as it's synthetic.)


blackman777,

A buddy of mine had one about 8 years ago and he reported nothing unusual except for the extra oil that the rotary consumed about one per month he had to put in a quart. I don't beleive he used any synthetic oil of any type.

He also didn't say anything about the seals blowing out nor needed replacing.

If I were you I'd just use a 5w-20 like the manual says and not the 40w cuz the rotary consumes oil like normal. It's the nature of the beast.

When you finally decide I'd consider another engine/car cuz I think after 2014 I believe Mazda isn't going to make any rotaries anymore but instead of concentrating on the "Sky Active" engine technology.

Durango
 
As I said I just like collecting cars with non-standard powerplants (the standard I4s or V6s are not interesting). It sounds like there will be another rotary in 2016:

"We were told by a Mazda USA insider (while we are all here together at the festivities in Monterey) is that the first application of the new 16X engine will be happening in two years' time in an as yet undisclosed new model." http://www.autoblog.com/2013/08/16/mazda-16x-rotary-engine-two-years-away-all-new-model/

Here's Mazda's own website about the engine: http://www.mazda.com/mazdaspirit/rotary/16x/
 
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