5W-20 was probably too thin for hotter weather. If you read my other post, I asked why Mazda used such thin oil.

Yes it's proven, the first # is for cold, the last one is for hot. If what I said wasnt true, every oil out there would be a 0W-50, something that would provide hot and cold protection.

 

ITs hard to NOT to make this kind of assumption

Seriously speaking, there's worst/better/same kind of weather as USA, but this is the only place that has this 5w20 bullshit and this is also the only place that has alot of engine failures and this is the only place that has this recall.

and the only thing thats different from here than the rest of the world is ... 5w20 and some ECU coding.

Theres a chance that Mazda might missed something when they de-tune the 8 when it first came out (due to emission, again)

We will not know the true answer. 5w30 that is (For me)

 

I don't see any issues with running 5W30. I actually am running 5W20 in my RX-7 even though everyone else runs 20W50. I'm only doing it because people told me I'd kill the engine with it. I haven't yet and I'm hard on that car.

Here's an interesting tidbit. We asked David at Speedsource about engine oil weights and what they have tried. He said there is no appreciable power difference between them. When I say "them" I am referring to 5W20, 10W30, 5W20, 10W40, 20W50. That's right, no appreciable power difference between 5W20 and 20W50. Interesting...

 

But don't you run synthetic oil? (Just wild guess. ) If there was really an issue of 5w20 dino being too thin, and 5w30 dino being OK, I'd expect 5w20 synthetic to be just fine.

Ken

 

No! I meant that even though 20W50 m.o. is farther away from Mazda's recommended viscosity than 75W90 gear oil, I'd still use 20W50 if forced to choose between the two.
I'm using 5W20 now.

 

You had me worried for a bit!

 

when I changed to 5w30 it didn't run better. I'm back to using 5w20.

 

Yeah, im using 5w-20 Castrol in my car, and its running just fine, ive had no problems whatsoever.

i mean thats considering oil changes every 3k and checking my oil everytime i fill up.

 

The other thing different in the US is the Freeways . Not too many other countries can you drive for hours on end at the same (high) speed with ambient temps as high as you get there .

 

This is not some problems that would show up right away, it takes YEARS before the problem show up.

but ahh, dont worry too much. like others said, not many people actually need new engine.

 

Perhaps it's the second different thing you mentioned that caused the failures; the ECU coding. Especially considering that's the thing that Mazda changed with the recall...

 

How cold and hot are 5w20 oils good for, what temp range? I live in N. Ca. and see 35 to 110F.

 

Keep in mind that most of the engine failures (not all) were on 4 port autos that don't get revved up and that have only 1 oil cooler. They were also in very hot and dry climates. There are just too many other things going on there to just blame it on 5W20 oil. If a 700hp 4 rotor could race at LeMans with a 30W oil for 24 hours and have over half it's engine life left after the end of the race, something's telling me that 1 step down to a 5W20 isn't going to hurt a street car with a third the power and far less abuse. If it did, practically every car in the US wouldn't come with it. Keeping tabs on oil temps are the number one thing to worry about.

 

So did anyone stop to think that 5w20 burns better. The pump is strong, no need for thick oil. heat transfer in the oil coolers aint it either. Remember everyone .. .
Your car is OIL INJECTED where piston engines are not. This is why running your engine to 9000 every now and then is good for it. to BURN off excess oil in the chamber.

 

I use Motorcraft 5w20 Syntec Blend- It's what my dealer uses....

I think it works just fine, and if there is something wrong with my engine in the future, at least I can point out that if it is a cause of oil type, they've been changing the oil for every-service schedule, so they can't blame me or somebody else that I'm using the wrong type of oil.....

 

Why not Mobil 1? I would like to use Royal Purple, but Mobil 1 is so much easier to get a hold of. What's the issue with Mobil 1?

 

Do you really feel like Mazda would mislead their consumer base adn want their vehicles to have problems? Geez.

How about just folow the manufacturers guidelines,although if you know better maybe you should work for them.

Dragon in 6 days.

 

Ask RotaryGod that question. lol.. More avialable and cheaper isnt always better just keep that in mind

And how come any thread about oil always turns to synth vs. normal? lol..

 

Mobil 1 apparently doesn't burn off in the combustion chamber as cleanly as many other oils, synthetic or nonsynthetic, and potentially causes more buildup in the engine. This is a result of the formulation and in reality has nothing to do with the fact that it's a synthetic. Keep in mind there is no official statement released by Mazda saying this but after talking to some high up people in the rotary world that appears to be the reason why Mazda says not to use synthetics. It only takes one bad apple to spoil the whole bunch and in a world of lawsuits it's safer to say not to use any of them rather than just to name one. Mobil 1 is the most widely used and available synthetic in the world so it's most likely to be the one tried by people. That's a problem.

 

RG, has there been any conclusions about castrol syntec? It's not a true synthetic oil, so I don't know if that means it burns cleaner than regular mineral oil, or if it's even worse than Mobile 1.

 

I used Castrol Syntec only once, for the 7K oil change. but I swap it to Advance Q after maybe 2 K miles. So Im not sure if its good or not. but its a bit rough on Syntec, Advance Q is smoother.

and I think Syntec is a Group-III oil. Synthetic or not ? ...... on paper is Synthetic. but it depends on how you look at it.

 

After studying how synthetics are made and what truly determines what is necessary to call an oil a synthetic, I am convinced that a group III is a synthetic oil.

I personally am a skeptic that Mobil 1 synthetic is going to do any harm. There are many people that have used it in rotaries with no issues. It's just a name that I got out of Mazda's head rotary person so it is suspect. I have personally use Havoline synthetic, Castrol synthetic, and Royal Purple synthetic (currently) and none have ever given me any problems.

 

Sorry to make this a late reply and beating a dead horse, but I thought I read in another thread that Mobil 1 had changed their formula from years ago and could not be compared to the synthetic they formulate today. I will confess, I changed my oil recently and used 5W30 Mobil 1. I am trying to pay close attention to the tail pipes for soot levels and will check the spark plugs (brand new) at the next oil change.

Let me throw out one last question and I promise not to ask another one about oil. Besides Royal Purple, what synthetic would you recommend? One that was easily available, of course.

I am a believer in synthetic oils for the rotary, but am still trying to figure out which one to use if I do not go with RP. Thank you in advance for your answers.

 

With the rotary burning about 1 quart every 800 miles, is it really cost justify to go synethic? I am not trying to start a fight here, but it seems pointless to me since you wont get the benefit of the longer life from the syn. oil. I guess you can say protection, but if i recall correctly, even the race car use regular oil. I don't know what you do to your car, but I can't see it needing more than regular protection unless you track the living crap out of the car.

I am a believer of synethic oil, I just don't use it on the rotary. My RX-7 did 90K miles in two years, heck it even overheated, but it ran fine even at 170K miles.

 

It depends on how you justify things. I know a lot of people that say you really can't justify owning a RX-8 and from their point of view they're completely correct. Some people like the piece of mind that comes from knowing despite the rotary's rather hot operating temperatures their own won't break down on them.