My Thoughts on RX-8 OILS,Tranny,Differential,Engine.
 

OK, my Series II has done now Just 4000 KM (2400 Miles), I have changed the engine oil 3 times (I will tell you why) and the Transmission and Differential Oils yesterday (first time) and the engine oil again while I was at it...

Differential OIL....
Old oil was a little dirty with some fine metal particles on the drain plug magnet.
Replaced with Redline 75W90 Gear Oil.

Transmission OIL ..6 Speed Manual
This really shocked me..it was almost BLACK (Dark Grey), with a huge build up of metal particles on the drain plug magnet.
Replaced with Redline MT90, the shift is magnificent, no 2nd gear lockout when car is cold (in mornings).

Engine OIL
I know this will be controversial, but, I changed Factory oil at 1000km, it was thin as water, rub between your fingers and I could feel my "finger skin prints".

So, I put in Mazda Australia's Rotary Engine Oil 5W30, after another 1500KM, and the Hot 40c plus degree Summer temperatures I decided to change it to a grade that IMO is better (and I will tell you why), when I drained the MRO I again was shocked just how dirty and black it was after just 1500KM and the viscosity test between my fingers was not much better than the Factory stuff. I Also changed the Oil Filter.

I decided to use Castrol (All Mineral 15W40), I drained that again yesterday after another 1500KM's and again the oil was very dark, BUT, the viscosity between my thumb and finger was 110% better than the MRO with the same mileage.
The oil still had "body" to it.

Sorry, I don't care what anyone says but the MRO is just not good enough for our summer temps...PERIOD!

I will use MRO in for winter...that is the only time I will.
There is just not the protection there, and I strongly believe that this is part of the reason why RENESIS's are failing.
Some engines (renewed under warranty) here are using way too much oil in a short distance which can only be the oil control rings worn out, hence the excessive oil use.
Why, not enough viscosity in MRO.

One time Mazda in the first 1000KM free service did a completer OIL change, including filter, Transmission and Differential.
They no longer do this, and it is WRONG.

MY advice to anyone with a new RX-8 or if you have not done your Diff or Trans, DO it NOW!..

The condition of my drive train oils was poor, particularly the Gearbox.

I also strongly believe that the "scheduled" oil changes and servicing is way too far apart, halve the distance at the very least to change ALL Fluids.

Leaving the original Transmission and Diff oil in your car according to Mazda's Service Schedule is WAY too long.

ALL I can say no wonder S2 Owners are having transmission problems.

Great writeup Ash, thanks for putting that information out there.

Being in Phoenix, we've experienced some of the hottest temperatures in the US and those of us in the rotary community locally cannot stress enough how important a thicker oil is during the hot summer months.

During colder climates when you don't see extream temperatures, a 5w-30 would probably be ok although I would stick to a 10w-30 myself. I have just decided to run 20w-50 all year long since it was a suggested oil from Mazda for the RX7 and the temps don't get low enough here to give me flow problems.

In the end, it's personal preference based on location, funds etc. Regardless of dino or synthetic, running a heavier weight oil in the hot summer is very important.

As for your Diff and trans oils...that's very surprising! With as easy as it is to change the transmission and diff oils, I have started doing both more frequently. If I had an auto I'd service it every 30,000 miles, but manuals are cake.

IMO, keeping fresh fluids in your car is the key to making it last above all else.

Could not agree more...

4 Years to change Brake fluid is also way too long...and coolant.

I really can't understand Mazda, it is almost like they want their cars to only last 100,000 Miles (160,000 KMS)...no revelation I guess..

AFAIAC to more you change ALL your fluids the longer the components that use/contain them will last longer., less corrosions, less wear...

Ash,

Thanks for providing another good conversation on the oil topic. I think your changes will be healthy for your car and I would recommend them to others as well. I don't ascribe to the finger viscosity test though :) nor the darkness of an oil being a proper indicator as to it's need to be replaced. When I first was trained as a mechanic over 20 years ago in Trinidad I was of the opinion that oil being dark represented it's need to be changed (Or was one of the criteria), when I heard others suggest otherwise I thought they were poorly trained or poorly educated on the topic. I later found that there was much more involved than that and that formulations can affect color quite a bit. It's a shame that you didn't send any of your oil samples out for lab tests to get thorough data on the ingredients of the various oils, their condition and the health of your engine over time.

As for why the manufacturers choose to use such seemingly high intervals; I think it's a combination of factors including the marketing end wanting their cars to seem low maintenance vs the competition combined with ever increasing global pressure from governments and agencies therein to use and discard less waste products. I think it's up to the consumer to research what's MOST healthy for their car's drivetrain. I like Red Line's 5W30 and 10W40 for our cars myself and then I would do a 5 to 6000 mile interval on the change with a filter replacement in between. I especially like this oil for very high antifriction additives (Good for apex, side and corner seals) as well as it's ability to maintain viscosity over extended periods and harsh climates like the potential fuel dilution found in rotaries.

Good work Ash and as I said before, I love your new car.

Paul.

I had the gearbox oil drain and out in the sun before I put it in a recycle/disposable container,
it sparkled with the sun on it, IMO ultra fine metal, or is it that coating Mazda are putting on their gears wearing off?...I just have not seen gear oil so contaminated in such a short milage..and I used to see many many 1000K owners cars oils when Mazda did do them at 1000K.

The black engine oil is showing a lot of carbon is getting in there in only 900 miles, Mazda increase the size of the oil filter by about 25% for S2 RX-8's, why?, IMO I still do not believe it is good for 10K or 6000 miles...and you can't install the larger type filter as it won't fit, there is a side flange(attached to front timing cover) in the way, I don't know why this 90 degree flat piece of alloy is there, appears to have no purpose, other than perhaps shielding the oil filter body.

Hi Ash

Did you cut open your oil filter at any point?

Here is a pic of mine at 1000Km from the .au forum. https://www.rx8club.com.au/forum/vie....php?f=5&t=849

I cannot stress enough to change fluids on a regular basis. It has really annoyed me that I have paid for a Mazda service and then had to drive home and finish the job.

Now that I am out of warranty I strongly doubt my baby will ever see the inside of a Mazda service center again.

By the way I like the colour choice.

Matt

Any preferences on the brand for other fluids, including brake, coolant, steering? Thanks.

electric steering... no fluid

my dad has an ap1 (2002) and he changes his diff and tranny oil at every 6-7k.. his tranny shifts so smoothly, no lockout in any gear at any time. its amazing. oh, and he has 80k miles

Thanks Matt,

No I have not cut open the filter, I am keeping them as my record/proof that my car was regularly serviced, I do not trust the Lawn Mower Mechanics (Mazda Technicians) at Dealers, the only time they will see my car is for warranty, so far nothing wrong.
BTW, Mazda Australia can not void ANY warranty if you do not take your car to a dealer, even though they may tell you so, as long as it has a "stamp" in the book.

My states consumer laws prevent them from doing so.
Great pics Matt, and no it does not surprise me at all, 15000 Km is way to long to change oil in ANY car.

I will chime in here...In Australia.

Castrol for Engine. 15W40 GTX 3 (RED Container) MRO 5W30 for Winter.
Redline for Diff (75W90 Gear oil) and Transmission. Redline MT90.
Castrol Brake fluid DOT 3. I don't know why guys are using DOT 4, the WS Manual specifically warns not to use it, perhaps someone can tell me why they do.
On your Master-cylinder cap it also says use only DOT 3 .

Coolant, I would use the FL22 which is available in the USA, Mazda Australia only sells 20 litre drums to dealers IF they buy it $250 AUD.
Most use a lower grade Mazda Coolant with less Etheline Glycol ratio.

Question about the viscosity
 

Hi I just got an 04 RX-8 and what you wrote intrigued me. What I was wondering was, since you changed to a thicker motor oil, did you experience any gas mileage change? I know that many newer vehicles use the lightweight oil in order to lower fuel consumption hence the energy saver label. Another thing I wanted to know is if you used good ol' dyno oil or the fully synthetic ones.

Good thoughts and more important actions! Redline in particular.

As a "human-machine interface", and therefore somewhat imprecise, the transmission fluid always gets dirtier quicker. Also, the differential gears stay 'mated' much more of the time of course than the xmission.

Here in a colder climate I like to go with a 5w, but for your locale/use 15w should be fine.

btw: change your 'plugs and air fliter more frequently then manual-scheduled and you'll be further impressed.

Great post ASH Good to see that you dont follow Mazdas advice blindly but are an independent researcher as to your cars individual needs in accordance to your driving style weather conditions etc .

Iwas also suprised to find the amount of metal shavings in the gearbox diff when i did my oil changes in my RX8

Currently in my modded RX7 I am running a Penrite HPR SAE 20W-60 INITIALLY I THOUGH THIS WAS TOO HEAVY FOR MY conditions here in Queensland but was adviced by my ex Mazda trained RX7 engine builder to stick with it as it protects my particular modded engine best .

Gomez on the other hand has a stock RX7 and according to his post is running with 10w - 30 So as the saying goes everyone to their own jugement .

sooo todd i should on my next oil change go from 5w30 to 10w30 or 20w50??? especially since its hot as hell already (101 two dayz ago ugh!) :icon_no2:

Not another oil thread!

Ash, you're right, we should change our oils more often, but you've over simplified the reasons why which really clouds the reason behind it.

On another note, I was using MRO for 100000kms and never really had a problem. I must say it was showing wear towards the end of a 10000km service interval, but it's not super-refined and is comparable with products of the same quality/price. Your oil can be too clean after an oil change as well (as it's not doing it's job ... just because it looks dark in colour, doesn't mean it's not working).

Your finger test of GTX3 vs MRO only proves that GTX3 is heavier at room temperature. To test whether the oil is still working you'd have to send it to a lab for them to test, you can't tell by looking at it.

I also have concerns with using thicker oil on a series 1 renesis due to the fact that our apex seals are already starved for oil, and yet our consumption of oil goes down with higher viscosity oils ... which is a bad sign for me.

Yes, oil consumption is a good thing, it's easy to forget it ... if your oil level isn't dropping in a rotary (at about 1L every 2000-3000kms depending on the way you drive) it's not good!

I am not going to buy into the engine oil debate but I will second the fact the Mazda intervals for diff and gearbox are ridiculous. Ash, you will find that while the fluid feels magical now, in 10,000km its going to be as bad as the last lot. I change both every 10,000k.

Cheers

Andrew

Where can you get magnetic drain plugs for the tranny and diff?

???, they are standard equipment on your Mazda already.

If for whatever reason you need a new one order it from a Mazda Dealer Parts.

Sitting at 36k miles, and I want to change my transmission fluid and diff fluid. I keep seeing MT90 as the reference. Are there other options? I respect RoyalPurple's oils quite a bit, and noticed that they have a MT fluid as well. Any reason against it? or is there a weight I definitely need?

^dont go with RP...itll mess up your tranny

So is MT90 the only option?

Not the only, but arguably the best.

Yes, very arguably ;)