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#851876 - 03/07/07 11:15 PM 5W-30 versus 5W-20 in Mazda RX 8
Able Offline


Registered: 03/05/07
Posts: 7
Loc: Florida, USA
Mazda USA requires the use of light 5W-20 weight oil in the RX 8 but through out the rest of the world Mazda requires the use of heavier 5W-30 weight in the same engine.

In the USA with the lighter oil the motors are over heating in warm weather and the engines are failing in slow trafic and on long trips within about 15,000 miles . The engine seals are failing and compresion is lost with the oil blowing into the catalytic converter which then is also failing. These engines by nature run very hot in the first place.

The dealership says I will lose the warrenty and the engine will fail sooner if I use the heaver oil. I don't care about the warranty and more about the engine being dependable.

Mazda requires this light 5W-20 weight oil to meet MPG requirements set by EPA to avoid million+ dollar fines.

What do some of you think ???

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#851877 - 03/08/07 08:43 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Able]
jaj Offline


Registered: 08/21/03
Posts: 891
Loc: Vancouver, Canada
I think a couple of things - of course I'm not an expert on rotaries, but that won't stop me!

First, read what AEHaas has to say about low viscosity oil and engine longevity and reliability. At high temperatures, SAE 20 and SAE 30 won't differ much in viscosity, and the 20 may cool better. The higher number may be a red herring. For reciprocating engines, lower vis improves piston cooling and bearing cooling as well as reducing friction. A win all-around.

Second, that warranty is awfully handy if there is a problem, and I doubt that the rotary designers would approve a lube strategy that was unlikely to work. The warranty expense for the mfr is a big one if something systematic is wrong. Furthermore, it's not clear that a lower vis oil will actually improve the economy of a rotary. Maybe instead of trying to improve fuel economy, they chose it because it just works better. Maybe they use 30 elsewhere in the world because 20 is not readily available yet.

Cheers
JJ

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#851878 - 03/10/07 09:39 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: jaj]
Able Offline


Registered: 03/05/07
Posts: 7
Loc: Florida, USA
jaj,

Thanks for your response. You made some good points to think about. In the USA, as noted above, the new Rotory engines have been failing before 20,000 miles and then replaced againnn and again usually after the warenty runs out. Most owners in the USA believe the Light 5W-20 oil required is causing the engine failures because the Rotory engine runs very, very hot and many think it breaks down the light oil in hot climates.

I notice you are in Canada and I am just curious what the Mazda RX 8 owner's manual in Canada requires to be used for oil ??? Could you call the Mazda dealership near you and check on the oil required. Of course the Canadan owners manual may read the same as all manuals in North America. Do you have access to 5W-20 ooil in Canada ???.......Thanks fot your thoughts on the subject

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#851879 - 03/11/07 09:33 PM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Able]
Mau Offline


Registered: 03/11/07
Posts: 641
Loc: Thornhill, Ontario, Canada
rx8 in canada requires 5w20 as well...

I would never run 5w20 and I don't see why it would void warranty if you do run other grades. I ran GC 0w30 in my prelude while it was still under warranty, honda did not have a problem looking at it and fixing any problems (I did have an oil leal)

Any who, here is an excerpt from the Canadian manual
http://www.wikiupload.com/download_page.php?id=101483
_________________________
07 Acura TL Type S 6MT - PP 5w30/Bosch 3323
07 Acura RDX - PP 5w30/Bosch 3323
04 Acura TSX - Motomaster Formula 1 5w30 Synthetic/Bosch 3323

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#851880 - 03/11/07 11:08 PM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Mau]
Able Offline


Registered: 03/05/07
Posts: 7
Loc: Florida, USA
Mau,

Thanks for the responce. Mazda USA must also affect what is in the manual for RX 8's in Canada or Canada also has miles per gallon requirements for a manufacture's car fleet, which must be met or be fined hundreds of millions of dollars, like in the USA.

The lighter oil results in higher gas miles for the Mazda car fleet, but the lighter oil also breaks down at lower temperatures than a 5W-30 oil in the very hot running rotory engine and the light oil also increases the engine temperature due to more friction of moving parts.

But what does Mazda care as long as their bottom profit line looks good............Later

I tried to use the link you gave in your response, but it just took me to a "home page" for a storage site and not to the oil page in the Canadian RX 8 manual.

Thanks for you response

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#851881 - 03/12/07 12:03 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Able]
Mau Offline


Registered: 03/11/07
Posts: 641
Loc: Thornhill, Ontario, Canada
goto that page and hit download file
_________________________
07 Acura TL Type S 6MT - PP 5w30/Bosch 3323
07 Acura RDX - PP 5w30/Bosch 3323
04 Acura TSX - Motomaster Formula 1 5w30 Synthetic/Bosch 3323

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#851882 - 03/12/07 02:35 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Mau]
Jim 5 Offline


Registered: 05/25/05
Posts: 4008
Loc: Calgary Canada
I would change my oil more often than recommended, or at least do UOA's to determine whether and how long this 5w-20 is staying in grade.

I would also consider installing a larger engine oil cooler and some provision for draining the cooler at each oil change. I understand that an oil change on these cars only drains something like 2/3 of the oil in the system.

Finally, there are a good number of RX-8 UOA's posted in the UOA section. Those UOA's might be very helpful in helping you make your decision.

Good luck and welcome to BITOG!
_________________________
Jim A
07.5 GMC Sierra 2500HD LMM Rotella 15w-40
09 Odyssey EX-L CT 5w-20
66 Bronco QS 10w-30
08 BMW K1200S Rt 15w-40
08 Pitster Pro X4 Rt 15w-40

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#851883 - 03/12/07 02:39 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Jim 5]
Jim 5 Offline


Registered: 05/25/05
Posts: 4008
Loc: Calgary Canada
I remembered another point. The twin turbo racing RX-7's ran two stroke oil in their fuel, and they found this extended the life of the Apex seals.

I remember reading about at least 1 Bitog member who routinely does the same thing. This is probably not advisable given that it might poison your catalyst, but it's interesting info in understanding the peculiar lubrication needs of these wankel engines.
_________________________
Jim A
07.5 GMC Sierra 2500HD LMM Rotella 15w-40
09 Odyssey EX-L CT 5w-20
66 Bronco QS 10w-30
08 BMW K1200S Rt 15w-40
08 Pitster Pro X4 Rt 15w-40

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#851884 - 03/12/07 10:21 PM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Jim 5]
buster Offline


Registered: 11/16/02
Posts: 29087
Loc: NJ
Where are you getting this information that engines are failing due to 20wt oils and how do you know it's the oil and not the engines itself?
_________________________
2014 3 S GT AT - OE oil
2003 Forester XS 5spd - M1 0w40

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#851885 - 03/13/07 11:08 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: buster]
Able Offline


Registered: 03/05/07
Posts: 7
Loc: Florida, USA
Buster,
I advised those who wanted more info on Mazda RX-8 engine failures can Google search the subject.

You asked how I know about the failures and the oil being the cause, well I suggest you read my blog untill it is clear to you what is causing the failures and then search other web sites for similiar information.

I have and RX-8 and I have first hand knowledge in addition to the researh that shows every RX-8 owner is having engines replaced in the USA but not throught out the rest of the world with the only variable being the oil used.

Buster, your question of how do I know is similiar to how do you know the sun comes up and causes heat.....duh

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#851886 - 03/13/07 06:27 PM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Able]
doctorr Offline


Registered: 02/12/04
Posts: 115
Loc: North Canada
I'm with the BusterMan - how do you come up with this theory that 5w20 is a cause of any engine failures?
You are in the wrong forum to start bashing 5W20 oils - they have proven over and over to be excellent lubes, and to cool better than a 30 weight.

Your claim that EVERY RX-8 owner is having engine trouble is just a deluded fantasy - likewise your claim that all owners blame 5W20 oils, because they "break down quicker, causing more friction". I don't know where you get this stuff, because it isn't true, on any level.

Mazda has been recalling cars to increase the amount of oil injected into the combustion area, the previous setting was not protecting the seals - if the compression is not up to spec, they provide a new engine, no cost to you. How is this a conspiracy? How can you get a new engine "againnn and again" and "before 20k" and yet still be "usually after the warenty runs out"?? It's kinda not possible.....
.
.
doc

Has YOUR '8 had a new engine? Probably not, only cars driven by grannies are having trouble, they never get the high revs that will keep the seals clean, so they carbon-up.

I know MANY '8 owners, and I know of only one who has had "more-than-one" engine, but it's been all at Mazdas expense - and no one blames their oil.

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#851887 - 03/14/07 12:25 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Able]
NYCGPS Offline


Registered: 03/13/07
Posts: 2
Loc: City of Garbage
Quote:

Buster,
I advised those who wanted more info on Mazda RX-8 engine failures can Google search the subject.

You asked how I know about the failures and the oil being the cause, well I suggest you read my blog untill it is clear to you what is causing the failures and then search other web sites for similiar information.

I have and RX-8 and I have first hand knowledge in addition to the researh that shows every RX-8 owner is having engines replaced in the USA but not throught out the rest of the world with the only variable being the oil used.

Buster, your question of how do I know is similiar to how do you know the sun comes up and causes heat.....duh




#@$%! dude, stop posting #@$%! when you have no idea what you're talking about.

Stop spreading #@$%!.

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#851888 - 03/14/07 12:27 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: NYCGPS]
NYCGPS Offline


Registered: 03/13/07
Posts: 2
Loc: City of Garbage
Not to mention you should get your facts straight before u posting c.r.a.p

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#851889 - 03/14/07 03:48 AM Re: 5W-30 versus 5W-20 in Mazda RX 8 [Re: Able]
Jax_RX8 Offline


Registered: 12/13/06
Posts: 345
Loc: Northern VA, USA
Quote:

Mazda USA requires the use of light 5W-20 weight oil in the RX 8 but through out the rest of the world Mazda requires the use of heavier 5W-30 weight in the same engine.

In the USA with the lighter oil the motors are over heating in warm weather and the engines are failing in slow trafic and on long trips within about 15,000 miles . The engine seals are failing and compresion is lost with the oil blowing into the catalytic converter which then is also failing. These engines by nature run very hot in the first place.

The dealership says I will lose the warrenty and the engine will fail sooner if I use the heaver oil. I don't care about the warranty and more about the engine being dependable.

Mazda requires this light 5W-20 weight oil to meet MPG requirements set by EPA to avoid million+ dollar fines.

What do some of you think ???




Unfortunately, you have taken a few true facts and manipulated them into an untrue story - with the help of a clueless dealer rep (as too many are). I too am an RX8 owner and a current member of the RX8club.com - I suggest you do some reading and learning there.

Key points:

1. Yes - 5W20 is the recommended oil. I use it and there are no issues with this weight although some prefer 5W30.

2. 5W20 oils allow greater flow and more cooling - so your theory on overheating because of the lighter weight oil is incorrect.

3. There have been a few engine failures (less that 1%) in mostly the 2004/5 models.

4. RX8's use an Oil Metering Pump (OMP) to inject a small amount of sump oil into the motor to lubricate the Apex and side seals - about 1 qt every 1000-2000 miles depending on how hard you drive the car.

5. The earlier OMP settings (which have now been corrected with an updated computer flash via a recall) did not inject enough oil for some extreme conditions such as very hot weather and very long idling - which caused some engines to have premature wear issues of these seals.

6. This excessive seal wear could cause low compression resulting in incomplete combustion of the fuel and flowing unburnt fuel to the catalyst and then frying the catalyst as well over time, so it is checked as part of the recall and replaced if necessary with the motor.

The key here is that there is no need to panic. All new vehicles have the new OMP setting and the existing ones are getting them as well as being checked for any premature wear and catalyst issues. Again, very few have needed engine replacements (like I said, less than 1%). So, use your 5W20, change the oil regularly, enjoy the ride, and do a little more research before pushing the panic button.

Regards

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