why rx8 needs 5w20?

Because that's the oil Mazda finds to be the most appropriate for a diverse range of driving environments.

My buddy has a 2003 civic and honda wants the 5w20 oil as well. He saw the price which is about double or more sometimes and started putting in the old standard 5W30...I'm guessing the lighter oil must have something to do with emmissions or fuel economy or something? Probably a better additive package in the 5W20 but who knows? He hasn't seen any problems? Yet.

5W-20 has a bit longer life than the 10w-30. The entire mazda fleet is pretty much going over to 5W-20. The 6's, Tributes, and for awhile the MPVs (which mazda came out and said to use 10-30W). And doesnt Ford use pretty much nothing but 5w-20 these days? If they do, I would bet that has somethign to do with on a political level.

Hmm...around here in Cali, the 5w-20 is the same price as the 5w-30. Both Castrol GTX.

Strangely enough I had a conversation with a Honda race engineer about this over a year ago. I asked him the same question but obviously it wasn't in regards to the Renesis engine. I suspect the answer is the same though. He stated that 5W20 oil is lighter and thinner and this puts less oil drag on the engine internally. Oils have come a long way in the past decade in their formulations. They are much more stable then they used to be even in the synthetics. An oil with less internal drag will give better power and better fuel economy. I asked him if there was any concern about such a thin oil allowing bearing surfaces to touch. He went back to the better formulations of todays oils. Basically almost any oil out there is better today than it was even 10 years ago. Regardless of the oils weight it isn't going to break down as easily like some of the older oils would. Everyone used to run a thicker oil since the oil would breakdown some and lose some of its lubrication ability quicker. The key then was bablancing this with an oil thin enough to be used when it was cold. Todays lightweight oils flow and lubricate at high and low temperatures very well. It is still very important to maintain oil changes every 3000 miles. Honda actually recommends every 4500 but better to be safe than sorry. The oil will still eventually break down but it is much more durable than it used to be.

As a test in my Honda Civic (slow daily driver) which does use 5W20, I changed for one period to 10W30. The car felt slower (if that is possible!) and the gas mileage went down. The next oil change I went back to the regular stuff and everything is fine again.

Honda uses the thinnest oil they can in all of teir race cars as well. There must be some truth to it. The guy I spoke with was quite intelligent and I don't think he made all of it up. Unfortunately I am only giving a very basic explanation of what he told me. I hope it makes some sense.

Good info there. I didnt know that. I drive honda and use 10w-30 so maybe I will make the swap in oil and see how it works out. Maybe that will shed a little more light on the oil debate in here

also, the reason why most companies are running such thin oil these days is to get the oil to all parts of the engine as quickly as possible on startup.

90% of all engine wear occurs on startup, so the faster you can get that oil flowing around, the better.

Ok, some "master of the obvious" stuff here, but I was trying to visualize what happens when you change the oil but only half of it drains out, as in the RX-8. Not sure what conclusions to draw, other than it may be more important than usual to change the oil frequently.

so your saying that after 24 months you have 8 different ages of oils?

OK,

Slap me silly and call me Susan but why does only half the oil get changed? I cannot imagine a car manufacture producing a car that only half the oil gets swapped out.

Is this a true Mazda thing or some backyard shop talk.

On my Ferrari's, all the oil came out...even from the oil coolers.

i dont think its half... 3.7 for each fill and ~2 in the oil coolers, right?

The standard power engine has a capacity of 6.4 quarts (w/ single oil cooler) and the high power has a capacity of 7.3 quarts (w/ dual oil coolers). When you drain all of the oil out during an oil change you are supposed to add 4 quarts (in both engine). After draining that leaves 2.4 in the standard engine and 3.3 in the high power still in the engine. Im going to check and see why, so give me a little time on that. My best guess would be this....

Because the rotarys burn oil (1quart for every 600 miles driven), it almost sounds like your doing an oil change before you even hit 3000 miles with out even taking it into for one. Im sure that the ratio is a rough number, so dont take it to much to heart. Perhaps Mazda sees it as the car burns oil, so the oil left over should have be relatively new since the customer probably added it. Thats my best guess, but I will check tomorrow at work.

Originally posted by SnyderMazz
The standard power engine has a capacity of 6.4 quarts (w/ single oil cooler) and the high power has a capacity of 7.3 quarts (w/ dual oil coolers). When you drain all of the oil out during an oil change you are supposed to add 4 quarts (in both engine). After draining that leaves 2.4 in the standard engine and 3.3 in the high power still in the engine. Im going to check and see why, so give me a little time on that. My best guess would be this....

Because the rotarys burn oil (1quart for every 600 miles driven), it almost sounds like your doing an oil change before you even hit 3000 miles with out even taking it into for one. Im sure that the ratio is a rough number, so dont take it to much to heart. Perhaps Mazda sees it as the car burns oil, so the oil left over should have be relatively new since the customer probably added it. Thats my best guess, but I will check tomorrow at work.

Thanks - I didn't factor in consumed oil. That, plus the fact that the new oil is actually more than 50% of the fill -- both of these factors will reduce the percentage of "older" oils in the system. I should factor these into a new chart but 600 miles per quart consumed sounds like a higher consumption rate than I've seen reported?

One other thing to remember too is that the oil essentially gets "homogenized" (yeah, it's a milk reference, but it works :) ). Your chart assumes that of the original oil, once half is changed out the other half essentially gets sequestered like the O.J. jury - never to see the light of day again. You'd have to accept that at some point the oil will become a thorough mixture like any other liquid and therefore get diluted as well with the next oil change. Fuel systems for navy aircraft are the same way, as only certain fuel is allowed aboard ships due to flash points; however, if one of the "land-only" types of fuel are used then after X number of refuel operations and the magic amount of ship-approved fuel is used at land bases, the aircraft is certified to be capable of ship operations again without having to go through a full de-fueling proces, etc. Make sense?

1 quart every 600 miles, hmm? I just put in 1/3 quart at around 1300 miles. whaddup wit dat?

just a couple thoughts here:

- race cars get oil changes before every race. longevity of the 5W20 oil is not a consideration, so it's not directly comparable. still I think 5W20 is just fine.


- if you really want to eliminate start-up wear then install a pre-start oil pressurizer. this is an electric pump that runs for a few seconds to send oil throughout the engine before you crank it. these have been known and used for a really long time, like 70 years or something.

Originally posted by S3/P3/E2
Your chart assumes that of the original oil, once half is changed out the other half essentially gets sequestered like the O.J. jury - never to see the light of day again. You'd have to accept that at some point the oil will become a thorough mixture like any other liquid and therefore get diluted as well with the next oil change.

I think we both agree but I probably didn't use the best graphical representation. Look again and I think you'll see we are really saying the same thing. By the 3rd oil change, there is only about 12% of the original fill remaining - the 9-month old stuff. Diluted 3 times, as you suggest.

As time goes on the percentage of the "original fill" (or any other fill) drops practically to zero. But it does hang around in appreciable amounts for a considerable time. If one were to follow a 7500 mile change interval then after the 30,000-mile change over 6% of your oil would have 30,000 miles on it!

Of course my 1st chart is grossly oversimplified. As already pointed out, there are losses due to oil consumption, and an oil change is actually more than 1/2 of the fill. Add intermediate top-offs which further complicate things. All of these items make the situation somewhat "better". However there's no escaping that there is significant amount of "old" oil that stays around.

What I'm curious about is what happens to these "old" oil molecules? I'd imagine they start to break down after awhile. I'd also guess that once that happens those "older fractions" are more likely to burn off, further reducing the old "population".

Conversely, though, I would also expect that this would result in a higher-than-normal amount of "cooked" by-products. Sludge, varnish, etc. What I really don't know is if this is anything to worry about or if the percentages are small enough to be taken care of by the fresher oil.

All I can say at this point is I am intending to keep a fairly frequent change interval; probably 3000 mi.

Maybe one of the oil gurus has more insight...

Guys

Here in australia all the rx8 s have only the 1 oil cooler , how does this effect the oil quality temperatures etc , when i questioned mazda as to why we only get the 1 oil cooler here in OZ they gave a lame answer saying that the weather here only needed the single oil cooler IMO it is B/s purely a cost cutting excerscise , on mazdas behalve.

michael

logically is like making a cup of hot choco... if more water is added to it, it beomes thinner n less sticky - easier to stir....

if we add more choco in it, it becomes thicker n makes stirring less smooth....

but thinner oil may not last longer n requires frequent change like those racing....
btw i using 10w.....(in between)

I just had my oil done at Rotary Reliability in Santa Ana, CA. These guys have been working with rotary engines since the early 80s. They even set the land speed record in 1983 (beaten by racing beat in 1985) in an Rx7. Anyways, those guys swear by 20-50 for rotary engines. Maybe the renesis is different, but for the most part, it's hard to disagree with people who have done nothing but work on rotary engines for over 20 years.

Slavearm

Nubo,

I think they just end up burning off from the heat or from the friction.

Go to the last page of this thread to see the "Mazda Driver's Guide" for the RX-8.

http://www.rx8club.com/showthread.php?s=&threadid=14616

Happy Zooming to all:D

If you read the entire post.....specifically page three. I posted the "drivers guide" scan a couple weeks ago....;)

Originally posted by Gyro
If you read the entire post.....specifically page three. I posted the "drivers guide" scan a couple weeks ago....;)

My regrets, but I've been following this thread and several others and no one seems to have gotten the message. I, for one missed yours, so maybe others did too? If you have posted the "Guide" previously, why are folks still looking for something from Mazda?????:eek:

Plus, I did give them the whole thing, including the part no. My post was a little more thorough!

is it "old" oil or is it X% oil contaminated?

Yeah, no argument w/ you there Nubo. I think you're right about "what's left behind." My biggest concern would be the metal particles, etc. suspended in the "old" oil that are still there even in a lesser number due to the half-an-oil-change procedure.

Originally posted by TybeeRX-8
If you have posted the "Guide" previously, why are folks still looking for something from Mazda?????:eek:


'cause it ain't in the owners manual and few owners received the "guide"

Originally posted by ProtoConVert
is it "old" oil or is it X% oil contaminated?

More like % oil contaminated. It's just a dilution effect. The fraction original oil (assuming no other additions) remaining as a function of the number of oil changes is just: 1/2^n. This also assumes a 50% mix. Under these conditions there's only about 3% 'original' oil remaining after 5 changes.

But, in reality the car uses oil. Mines uses about 1qt/1000 miles. If I change every 3000 miles I will have added 3qt additional oil. Frankly, I think the car's oil stays pretty clean as a result. Constant turnover.

Originally posted by VelocityRedRX8
More like % oil contaminated. It's just a dilution effect. The fraction original oil (assuming no other additions) remaining as a function of the number of oil changes is just: 1/2^n. This also assumes a 50% mix. Under these conditions there's only about 3% 'original' oil remaining after 5 changes.

...and then the mathematicians showed up to embarass "the feeble-minded ones." :D

Good to know someone's got a 10 lb. brain around here.

Originally posted by Nubo
All I can say at this point is I am intending to keep a fairly frequent change interval; probably 3000 mi.
Honestly, I don't intend to stir up some sort of a religious war about oil change intervals - but I fail to understand why would that be beneficial when Mazda recommends a 7500 mile interval...
I intend to stick to their recommendation - there has to be a reason why did they come up with that specification.
IMO changing oil every 3000 miles will only make thei oil companies rich (and eventually the service stations performing the changes).

Depending on driving conditions they also have 5,000 mile interval. Since I got free service that's the one i'm using plus I'm throwing in a fresh quart every couple thousand..

Originally posted by Tamas
Honestly, I don't intend to stir up some sort of a religious war about oil change intervals - but I fail to understand why would that be beneficial when Mazda recommends a 7500 mile interval...
I intend to stick to their recommendation - there has to be a reason why did they come up with that specification.
IMO changing oil every 3000 miles will only make thei oil companies rich (and eventually the service stations performing the changes).

Many other vehicles specify a 7500 mile change interval, but their oil changes result in close to a complete change-out. With so much oil remaining in the RX-8, you would have to change more frequently to approximate the effects of a 7500 mile change for other cars.

I suppose used-oil analysis will tell the real story. Until then I'll err on the side of caution, especially with tales of the engine running abnormally rich.

Economically I'll mitigate the effects in 3 ways. For one, I've decided to run conventional oil instead of the synthetic I've been running in my current vehicle. Secondly, no service stations are going to get rich -- oil change is DIY. Third, I'll change oil filter every other oil change.

Hey guys,
I just had my oil changed in my rx8. On my way back from the dealership I looked at the sticker and it says Quaker State 5w20, which is what is should be. But then I look closer at the sticker and it says "synthetic blend"??? What the hell? Aren't they supposed not to use synthetic??? I know it is not fully synthetic oil (it is just a blend) but still it does not burn so easily... I guess I have to call them back and make sure that they know what they are doing.

Ok guys,
I just called them. They say 5w20 quaker state synthetic blend was approved by mazda for rx8. And this is the oil they specifically got for rx8! End of story.
I guess I just replied to my own message. Well hopefully somebody will find it helpful.
Thnx

Quick response you got too!

very interesting

I wonder if they are just saying that because they made a mistake

The owner's manual is gospel - it has all of the technical specifications. The guide is an overblown sales brochure, IMO.

btw i m using 10w50.....

Originally posted by khoney
The owner's manual is gospel - it has all of the technical specifications. The guide is an overblown sales brochure, IMO.

Exactly!!

Read my comments in the thread. MNAO has not officially notified owners that you can't use synths. Sure the brochure is great, and I wish that everyone got one with their purchase! Unfortunately that's not the case. But we have this great forum to share this kind of info ;)

Don't we also have oil metering to think about? If the system is set up for a specific viscosity and we you something thicker won't less oil be metered?

Just a thought.

Vince

I guess it depends on expected temperature ranges.

In UK the cars are supplied with 5w30.

Anyone know what engine oil we should use for winter time? Still 5W20

Must not be critical then. Thanks!

Vince

Originally posted by Vrimmick
I just called them. They say 5w20 quaker state synthetic blend was approved by mazda for rx8. And this is the oil they specifically got for rx8! End of story.
I suggest a follow up phone call to MNAO to see if 5w20 Quaker State Synthetic Blend IS approved by Mazda for the RX-8.

If so, great! If not, looks like a trip back to the dealer for another oil change (on the house).

I guess the next step less viscous than 5w-20 would be 3-in-1 oil? (yes, I'm joking)

IMHO, none of the differences between the Renesis & previous rotary engines would negate the rational behind not using synthetic oil. My understanding is that the Renesis requires less oil to be sacrificed into the combustion chamber but there still is an oil metering pump so some oil is still sacrificed & synthetic oil leaves a resin like residue when burnt. One thing that I’ve learned as I’ve aged is to trust my judgment…I’ve been burned (no pun intended) many times by ignoring my judgment in favor of one from an individual possessing greater authority or credentials.

WARNING – Characteristic Red Neck Sounding Rant - WARNING

100% Dino for me regardless of what some guy in a lab coat sez’.

Good luck finding ANY 5w20 oil that is NOT partially synthetic.

In order to pass the extended/double sequence testing, most are blends.

Synthetic oil burns just as easily as any other oil. Spill some on the exhaust manifold. This is an easy way to compare oils. Most synthetics burn cleaner than mineral oils.
If you don't believe this, BURN SOME YOURSELF!

5w20 provides the same protection as any other weight oil. The important thing is that the engine must have some type of control over oil temp.

If the temp of the 20wt oil is 20F cooler, then it is as thick as the hotter 30wt....... How many oil coolers do you have? foreign market cars have????

Also, these oils pass more strict testing for use in Mazda/Ford/Honda applications.

Originally posted by deadrx7conv
Most synthetics burn cleaner than mineral oils.
If you don't believe this, BURN SOME YOURSELF!

Bingo! I wonder if those who say synthetics don't burn as clean have actually ever seen results of combusting synth oil vs. dino oil. It's the exact opposite - dino leaves a sludge if anything does.

Mazda won't recommend or approve (or disapprove) any specific brand of oil, or they leave themselves open to lawsuits. Further, US federal law prohibits manufacturers from requiring any specific brand of fluid or lubricant for warranty purposes unless they provide that fluid for free - Ferrari has run into that already, where they tried to require owners to pay $60 per quart (yes that's right, sixty dollars per quart) for a special Shell synthetic oil for the Enzo, and said that warranty would be void if they didn't use the special Shell oil. Very quickly Ferrari North America was reminded that if they required only that oil, and that generic oil meeting a specification (say, the way Mazda specifies API SL spec 5W20 for the RX-8), then they would have to provide it for free to Enzo owners. Long and short of it is - Mazda can NOT void a warranty on any engine that has followed maintenance intervals with the specified oil, that specification being API SL 5W20. Period, no mention of dino or synthetic. If your synthetic oil of choice meets API spec SL, it's fine.

Regards,
Gordon

Gordon: That is the most common sense response I've seen on this whole "oil thing" yet. You are absolutely, 100% correct. API specs are what matters and the Ferrari issue was very well known in certain circles.

Use what feels right for you, as long as it meets the Mazda specs; nothing else is pertinent (at least as to oil) to the life of your car.

Why 5-20? 'Cuz Mazda says so, and they know more about this engine than we ever will. Since they don't sell oil, they have no icentive whatsoever to tell us owners the wrong viscosity.

By the way, if you saw Rusty Wallace on MotorWeek this week, you learned that his race car uses 0-30 weight oil. So much for low-viscosity not having enough protection.....

I recently read up on oil and discovered there's lots of reasons why 5w-20 is used a lot these days. First of all, it's thinner and this is good for many reasons. For one thing, it being thin makes it easier to flow during startup when the engine is cold. This is good whether it's cold or hot outside; it's still thinner than other oils no matter what temp. For another thing, because it's thinner, it requires less energy to move around inside the engine, thus the engine doesn't have to work as hard to move pistons up and down and this leads to better gas mileage and reduced emissions. I'm guessing it's used in the rotary because it spreads more completely within the trochoid chamber which is essential for a long lasting rotary engine. These days engines are built with such precision that thicker oil doesn't always have to be used to seal moving parts such as pistons and chambers. These days thinner is better for all kinds of reasons. Probably the biggest reason is to make it easier for engines to meet emissions requirements in the U.S.

Been reading alot on this forum about type of oil 5w20 and the such...well im aksing about brands ...which brand of 5w20 would you consider the best...i know its not supposed to be synthetic.....the area I live ..ive found 2 options..

Penzoil ( 5w20 with PureBase *stop and go protection it says* ) not sure if its synthetic

MotorCraft (5w20 *premium synthetic BLEND*) ...it also says its designed and recommended by FORD

so what do you guys think brand wise..specially from the 2 ive listed..

thanks

Originally posted by mrpooh
i know its not supposed to be synthetic

Um, read this thread (http://www.rx8club.com/showthread.php?s=&threadid=16430) - Mazda now says 'upon further testing, synthetic is OK'.

Therefore - use Mobil1, Redline, Castrol Syntec, etc.

FWIW, I would avoid any pennsylvania crude-based oils. It's probably not the case any more, but Pennzoil and Quaker State oils used to be the very worst for wax and sludge build-up, a consequence of their source crude oil composition.

Regards,
Gordon

Gord, avoiding a Pennsylvania crude based motor oil shouldn't be too difficult considering that daily production in Pennsylvania is currently 6000 BPD (less than 1% of US production).

I see no good reason to avoid Pennzoil or QS based on ancient history or anecdotal evidence.:)

yrotory

Originally posted by Gord96BRG
Um, read this thread (http://www.rx8club.com/showthread.php?s=&threadid=16430) - Mazda now says 'upon further testing, synthetic is OK'.

Therefore - use Mobil1, Redline, Castrol Syntec, etc.

FWIW, I would avoid any pennsylvania crude-based oils. It's probably not the case any more, but Pennzoil and Quaker State oils used to be the very worst for wax and sludge build-up, a consequence of their source crude oil composition.

Regards,
Gordon

Gordon,

Again, I'm no expert on oil. I used Mobil 1 in my previous ride. But don't you want to do an oil change to get to synthetic if that's the way you are going to go? I thought I heard you never mix synthetic with fossil? Or is that an old wise tail?

I think given a choice you'd rather have all of one or another, but most synthetics on the market are 100% compatible with regular dino oil and ought not cause any problems at all.

although politically incorrect, I think you meant "old wive's tale"

Castrol, 5W20, dino.

using Mobil1 SuperSyn 0w-20 here.

I just took my car in for its free 4 month check up/oil change and I just looked at the bill and it says 4 qts 10W30 oil!!! I really hope this is a typo.... no clue why the hell they wouldn't put 5W20 in like the manual and oil cap calls for.

Anyone think this is serious enough to hassle the dealer and waste more of my time? Will 10W30 be all that bad for winter??

think I saw a post a while back where same thing happened to someone else -- he/she pointed it out to the service folks, and they replaced the oil *two* more times to flush (most of) the wrong-spec oil.

I'd be sorely tempted to demand exactly that, since mazda (corporate) seems so persnickety about 5w20 SL...

call them and ask what they used

Yes this just happened to me, my dealer put 10w30 in. When I saw this I raised the issue with them. The response was since I'm on the freebie service plan if I want 5w20 I would have to pay for it because Mazda won't re-emburse them for going out and buying 5w20 because they don't stock it for services. The dealer claimed that 10w30 is just as good if not better. I'm not a happy camper.

In Australia the recommendation is 5w-30, not 5w-20. Although the my local dealer insists with the hot climate we have (in Adealde, South Australia, 40C last week - well over 100F) and lots of highway driving, then 5w-50 is an option worth considering.

One of the local rotary performance shops here uses 0w-30 on their race cars.

Originally posted by Artifex
Yes this just happened to me, my dealer put 10w30 in. When I saw this I raised the issue with them. The response was since I'm on the freebie service plan if I want 5w20 I would have to pay for it because Mazda won't re-emburse them for going out and buying 5w20 because they don't stock it for services. The dealer claimed that 10w30 is just as good if not better. I'm not a happy camper.

ok... now i'm going to call my dealer up on monday. If they are doing that to me too they have some hell to pay. Christ, every new Mazda takes 5W-20!!!

You need to get a manager at your dealer to sign on that, then call Mazda corporate. It's a requirement for them to be dealers to have all the proper supplies and if they wanna charge ya extra, they are looking at loosing their dealership (especially if you can find another couple of epople witht he same prob). They CANNOT be an authorized dealer and not service the cars with the required components. DONT let it slide! Call Mazda ASAP about this and report them.


Originally posted by Artifex
Yes this just happened to me, my dealer put 10w30 in. When I saw this I raised the issue with them. The response was since I'm on the freebie service plan if I want 5w20 I would have to pay for it because Mazda won't re-emburse them for going out and buying 5w20 because they don't stock it for services. The dealer claimed that 10w30 is just as good if not better. I'm not a happy camper.

hmm you make sense,
I will be back at that dealership the week after Christmas and I will do just what you describe. Either the manager replaces the oil or signs a statement saying his reason for not doing it. I will then take the issue up will mana.

Thanks!

I should be picking up my new RX8 today and I'm alreday thinking about doing my first oil change. Can we use Mobil 1 synthetic in these engines, if so what viscosity would be the best?

Ok, before any of the wolves can get to you first, there's a whole slew of posts on here about synthetic vs. conventional and whether or not it's okay. Even Mazda has come out and said ok but reversed themselves days later. Ultimately it'll be up to you. Take a look for these posts by using the search function at the top.

As for the rest of you - BACK!!! BACK!!! :D

Thanks much for the heads up !!!!!!

Hey,
10w30 is probably as good as 5w20, the only reason mazda recommends it is because of fuel economy. 5w20 has less friction and saves gas, but 10w30 is a better protection for your engine.

I called up and the service manager claims that 10w30 comes up by default on their computer system and unless the technician willfully changes it, it will always read 10w30. He claims they put the right weight oil in.

So if he's lying or not I have no idea unless I pay for an oil analysis which isn't going to happen.

I would make sure they put in 5-20. I don't see how 10-30 could/would be better protection. 5-20 will flow faster/easier in the cold (important during startup) and will have less 'drag' at operating temperature. With the 8, the less drag on the engine, the better for fuel economy.

I bring my own oil to the dealer for the oil changes and I only get charged for the filter and labor (approx 13 dollars).

Originally posted by pr0ber
I called up and the service manager claims that 10w30 comes up by default on their computer system and unless the technician willfully changes it, it will always read 10w30. He claims they put the right weight oil in.

So if he's lying or not I have no idea unless I pay for an oil analysis which isn't going to happen.

ask for the empty oil containers next time. if they dont stock 5w-20 they'll have to get it somewhere else.

Originally posted by Artifex
Yes this just happened to me, my dealer put 10w30 in. When I saw this I raised the issue with them. The response was since I'm on the freebie service plan if I want 5w20 I would have to pay for it because Mazda won't re-emburse them for going out and buying 5w20 because they don't stock it for services. The dealer claimed that 10w30 is just as good if not better. I'm not a happy camper.

Definately call Mazda about this and see what they can do for you!

Most dealers will stock drums of oil as it cheaper. Most of them have not bought 5w-20 in any quantity yet.

That's probably why the dealer is demanding more money, but the owners manual is the bible of service for the consumer ;)

I gave my car it's first oil change at 3000 miles. The 5w20 I drained out couldn't even cling to the sides of a clear plastic container. It had the viscosity of somthing like milk. I will not be using 5w20 ever.

Originally posted by nyspeed
I should be picking up my new RX8 today and I'm alreday thinking about doing my first oil change. Can we use Mobil 1 synthetic in these engines, if so what viscosity would be the best?

If you decide to go synth (I did, with AMSOIL XL-7500 5w-20), you should probably wait until you put some miles on the car. I'd do one oil change with dino, and the next one synth. I just used 5w-20, which is what Mazda recommends.

I've been to my local store a few times now and want to be certain before topping off my oil. I now have about 1300 miles and its time to add some. I've seen Castrol 5w-20 (SAE). I do not know what the SAE and have been thinking about it with no success. What is the exact type of oil everyone is using. I understand people will and are using different types but I'd like to know. I know there are several other threads about this but I couldnt find a solid answer. Maybe there is not one. Thanks.

SAE = Society of Automotive Engineers.

They establish a blue million standards for materials used in cars, including lubricants. The Castrol 5W-20 meets the SAE oil standard called for in your RX-8 owners manual. I personally bought a case of Motorcraft semi-synthetic 5W-20 and am not gonna agonize over oil choices- I'm just going to change it every 1,500 miles or so.

Hi KFence27,

I use Castrol 5W-20 (silver/grey top).

Here's a link explaining the markings on a motor oil label:
http://www.chevron.com/prodserv/nafl/auto/content/motoroils.shtm#choose

Happy New Year,
rx8cited

Thanks a lot for the link, helped out. Theres so much to learn in this forum my head is spinning, but its all good stuff.

Hey all,

I heard that the RX-8 (which I should be getting around the 14th) consumes a large amount of oil because of the wankel engine. But I wanted to know your take on things?

Does it need lots of oil..and how much..and how many times per say.month or week. Thanks all!

CM

More oil the harder you drive.
If you drive it normal, then maybe 1/2 qt or much less a month.

I've done track days and have consumed a quart in the daily sessions ;)

It's simple, check the oil often, not a big deal!

Nice to see you referred to the 8 "consuming" oil. Some people have been using the word "burn," which gives the wrong impression since the RENESIS is designed to use the oil in the combustion cycle.

Originally posted by CriticalMass
and how many times per say.month or week.

It's not a function of calendar days, but miles and how hard you drive. ;) The highest consumption I've heard of is around 1 quart per 1000 miles, many are finding that they only have to add 1 quart every 1500, 2000 or more miles.

Regards,
Gordon

2000 per quart seems about right. But then what I dont get is why the oil gets black so quickly. After a week of driving after doin an oil change. The oil gets black. Does it have to do with the oil being burned?

In my 8 (231CV European version)

2.560 km --> 0,2 liters of oil

I think this is not a big consumption :) :)

I must drive like a wimp, I just added my first quart at 2,600.

Originally posted by sohcpunk
2000 per quart seems about right. But then what I dont get is why the oil gets black so quickly. After a week of driving after doin an oil change. The oil gets black. Does it have to do with the oil being burned?

You are not changing all of the oil - the oil in the coolers is still old oil. There are 7.1qts total hiding somewhere in the system - the most I've been able to drain is about 4 3/4.

I get an oil change every 5000 (recommended interval under harsh conditions; normal interval is 7500 miles.) I add one quart between each oil change. It's not that bad.

Originally posted by pr0ber
I called up and the service manager claims that 10w30 comes up by default on their computer system.......

hi pr0ber,

FWIW, I got the same story from a local Mazda service department. He said the ticket will say 10w30 regardless of which oil they put in the car.

regards,
rx8cited

I don't want to have to make an appointment at the dealership to get an oil change. Can I go to oil change places??? And will they have the 5w20 oil as well as the oil filter that our cars require? and last is the oil change on this car any different from any other car...by that I mean do we have to drain the oil coolers as well.... these are questions that I want to make sure I get answered before I go to my local shop.

The first shop I stopped at wouldn't touch my car because it's not in their computer. The second shop made some phone calls and found the right filter. Unfortunately, they did use 5W30. I'm going to leave it in untill I get to 3K miles. I decided to change the oil at 1K after speaking with some other local owners. When I go back, they'll get the viscocity right, and use synthetic as well.

your going synthetic? I thought that wasnt a good idea?

Originally posted by tommy12g
your going synthetic? I thought that wasnt a good idea?

Synthetic is all the german dealers use.... it is a Guinuine Mazda Synthetic Oil

I had an idea and I don't what it would accomplish but since I've got all this extra motor oil that I'm not going to use, could I use it to flush out the old oil?

We know there are about 7 quarts in the engine but only about 4 come out when you drain the oil pan. If I leave the oil pan plug off and pour in a few quarts, do those quarts mix with the 3 old quarts or so that do not drain? Or do those "flush" quarts go straight through to the oil pan and do not mix with the oil still in the engine? The idea is to get as much new oil in the engine as I can. The way we change oil now we're only getting about 60% new oil and 40% old oil is still in the engine.

No, tommy, the new oil would come right out of the plug hole.

The 'old' oil has been pumped into the coolers, and hoses, and a fair bit sits INSIDE the rotors, (they are hollow) so it will never drain out.

If you put the plug back in THEN add 4 jugs of new, you could start the engine, and it would all circulate and mix. Then you could drain it and get some of the 'old' stuff out.

A bit wasteful, but if like you say, the oil is just going to waste anyway, then you can flush it like that.
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doc:cool:

Doctor I wasnt the one that asked the question, but thanks for the explanation anyway

Wow - and here I was just looking for a post that might say something about tefloning the engine after break-in. I've done it to my last 3 vehicles and they have lasted forever (well, until I handed them over to my kids or buyers - one I'm still driving). Anyway - it makes sense not to burn synth just because of cost, if it's going to be consumed, it'll have carbon embedded as soon as it's introduced to the engine, and the statements about deposits being left behind make sense, also. I keep pretty good records and enjoy working and maintaining my own vehicles - I know what's being done and how, that way. But - I gotta say I was surprised to read in this thread that only about 4 - 1/2 qts. will come out while the remainder stays in the circulation system? Wow, again.

We just got our Rx a little over a month ago and the elation of the exceleration response has consumed a little over a half a quart at 1150 miles.

And that makes me think of the original question which had me looking for other owner's experience:

The point of using a lighter weight oil was to deliver it as quick as possible since startup is when the majority of damage occurs - and that's my reasoning for treating the engine with a teflon bonding product. Not Slick50 or the other ones you can but premixed, but I buy a pint of the straight PFE additive from a local parts store and I'm very happy with the experiences I had in doing so. Is there anybody that would advise AGAINST doing so?

And in a prior thread I read about the "Tornado" air intake add-on. While I feel it made a difference in my Tacoma in mileage alone, I wouldn't want to add this to my Rx. I'm glad I caught that one......

Man, can't wait to learn more, y'all.............

Tall...........

Originally posted by Tall Corn
Anyway - it makes sense not to burn synth just because of cost, if it's going to be consumed, it'll have carbon embedded as soon as it's introduced to the engine, and the statements about deposits being left behind make sense, also.

The point of using a lighter weight oil was to deliver it as quick as possible since startup is when the majority of damage occurs - and that's my reasoning for treating the engine with a teflon bonding product. Not Slick50 or the other ones you can but premixed, but I buy a pint of the straight PFE additive from a local parts store and I'm very happy with the experiences I had in doing so. Is there anybody that would advise AGAINST doing so?


No, actually it does NOT make sense to avoid synthetic because a very teeny amount of oil is burned - out of about 7 litres in the system, you might burn 1 or 2 litres in 5000 km? Synthetics provide much better protection for lubrication; I wouldn't want to drop down to mineral oil just to save $3 or so on the oil that's combusted. Further - the idea that synthetics leave behind deposits is nonsense - they burn cleaner than mineral oils.

The point of using a multi-grade viscosity oil is so that it's lighter than a single grade when it's cold, providing better protection at startup. The viscosity of a 5W20 and 5W30 is IDENTICAL when cold - the first number(5) is the cold viscosity, the second (20 or 30) is the hot viscosity.

For me, personally (mechanical engineer), I would never use any sort of additive in the oil - DuPont themselves will tell you that Teflon additives are useless in engines at best, and possibly harmful (I believe it's even on the DuPont Teflon information web sites).

Regards,
Gordon

Originally posted by Gord96BRG
No, actually it does NOT make sense to avoid synthetic because a very teeny amount of oil is burned - out of about 7 litres in the system, you might burn 1 or 2 litres in 5000 km? Synthetics provide much better protection for lubrication; I wouldn't want to drop down to mineral oil just to save $3 or so on the oil that's combusted. Further - the idea that synthetics leave behind deposits is nonsense - they burn cleaner than mineral oils.

The point of using a multi-grade viscosity oil is so that it's lighter than a single grade when it's cold, providing better protection at startup. The viscosity of a 5W20 and 5W30 is IDENTICAL when cold - the first number(5) is the cold viscosity, the second (20 or 30) is the hot viscosity.

For me, personally (mechanical engineer), I would never use any sort of additive in the oil - DuPont themselves will tell you that Teflon additives are useless in engines at best, and possibly harmful (I believe it's even on the DuPont Teflon information web sites).

Regards,
Gordon

ok, that's all fine and said, but sometimes I'll need to see results in documented lab testing - being the skeptical guy I am. I read so many different opinions on this subject, it gets to be very confusing. And not like I'm never wrong, but I do rely upon personal experiences and be it either the advance in automobile manufacturing technologies or compositions of engine block alloys or whatever - I keep all my autos well into 10 years plus. The engines that have lasted the longest without oil consumption have been the ones that I have treated every 50,000 or so and have been a big fan of Castrol GTX 10W40. I had a 86 Pontiac that I experimented with nothing but Mobil 1 in it it's whole life and it did wonderfully until I gave it to my daughter. No visible varnish or deposits that whole life I had the car. I made my '76 Astre (a Pontiac version of a Vega) last 179,000 miles on its original engine - an almost miracle from what people saw me driving it would say. Maintenance pays for itself.

You see, like others, I'm sure - I really love this Rx and have plans to keep it forever (well, while I'm walking or should I say zooming around this earth). I just want to make sure I'm doing the right thing to my baby.

I will go out and keep looking at all the information and articles and test results, but the sake of argument is not enough to make me go one way or the other concerning synth or dino.

I would want to know what Mazda's warranty states I can or cannot use, and I haven't read that thread or seen any manufacturing statement, yet. Not that it's not out there, I just haven't seen it. I mean, they engineered the dang thing........

Tall..........

Originally posted by Tall Corn
I would want to know what Mazda's warranty states I can or cannot use

Mazda requires 5W20 (in North America - everywhere else, they spec 5W30), with API spec SL. That's it - no mention of not using synthetic.

Re burning synthetic, etc. - there are several comparative studies on the internet with dozens of synthetic and mineral oils analysed and detailed results posted. A good place to start is www.bobistheoilguy.com .

Regards,
Gordon

I changed to synthetic oil but now Mazda states thatthey do not recommend it. How can I change back to conventional oil. I hear that once you go synthetic, you can't switch back.

You people have mw so confussed :confused: i know alot of you have had yor cars for some time now i just bought mine 1 week ago a 2005 AU TRAN i am so confused on the proper oil to use please let me know if you have had this car now for more then 6 months. I don't want to make a mistake.
Thanks

This is (and always has been) a very controversial topic. You will get several different answers to your question.

For me, it all comes down to this.

If you keep your oil level full and changed routinely, you will never see any real difference between synth and dyno (non synth) oil. I am very picky with my car, and drive it real hard. I use valvoline 5w20 standard oil.

Somewhere along the way Mazda recommended using non synthetic oil for the rotary, without really explaining why. Some say its because dyno oil burns easier than synth oil does and the rotary engine burns oil by design.

I was involved in a few articles for RXTuner magazine which required me to follow a Racing team's progress with the RX8 in SCCA. This team has had years of experience with racing RX7's. If you want to see a rotary engine pushed hard, try 45 minutes of full throttle at 8500 RPM's in the heat of summer. They use synthetic (10w30 I believe) without any problems.

My advice is to use a quality oil at the 5w20 weight. Keep it changed and full on the dipstick. Beyond that... dyno or standard.....use what makes you feel better, because I won't make any discernable differce throughout the life of you car.

You people have mw so confussed :confused: i know alot of you have had yor cars for some time now i just bought mine 1 week ago a 2005 AU TRAN i am so confused on the proper oil to use please let me know if you have had this car now for more then 6 months. I don't want to make a mistake.
Thanks
Why are you confused? Go by the manufacturers recommendations in the owners manual that came with the car and you can't go wrong. Simple.

You will NOT get a definitive answer on this forum to the question of what kind of oil to use. The topic has been debated on this forum ad nauseum, so if you really want to delve into the topic, do a search and spend the next couple of days reading all of them. In the end, you will be just as confused as you are now.

thanks guys

Don't worry about it. You can mix any brand or weight of oil with no fear of damage.

The only concern might be if you were to switch to synthetics at a high mileage. You might start to see some leaks.

I used to have a Mustang Cobra that had used Moble 1 since it was new. It had developed a couple of small leaks that weren't worth the cost of fixing. At 140,000 miles I changed to regular oil and the leaks mysteriously disappeared. When I researched this on the internet I found that quite a few other people had the same experience.

I recently sold the car with 215000 miles and it was still strong. So half it's life was with synthetic and the other was with regular oil. But I always changed it regularly.

Well, I've read every thread on this forum I can find about oil, brands, changes, synthetic vs. petroleum and I have to agree with Gyro, "Use a quality oil at the 5w20 weight". All this reading and trying to decipher what is best just hurts my brain. I'm going to buy a case of Valvoline or Castrol, whichever cost 2 cents less and not read another thread about oil changes.

I will do as Charlie "marietta_8" of Mazcare in Marietta, GA suggested to me the other day; purchase Mazda oil filters, tear the top flap off and write the date of the oil and filter change on it and file away in records for warranty purposes.

Now, I'm done with this subject!

Motorcraft 5W20-1 quart about evey 1500 miles-factory fill i think-can't be all bad!

i have had my RX8 now a few month i found that they have castrol 5w-20 partial synthetic oil i think this is what i will be using it was around $11 for a 5Qt container just thought i would pass the info along.