Hey Club!

Just recently picked up my RX8 (used '05) and was told by the previous owner that the dealership was putting 5w30s in it. Today, I went to get an oil change @ Rotorsports (Bay Area, CA) and I noticed on the receipt that they used 5W20. Should I be worried?


SanQ~!

 

oh my god ...

 

You are asking a question that is very debatable. Alot of us use 5W-20 including me and I havent had any problems with over 50,000 miles in seven years. Others swear by 5W-30. I just recently ordered some ProteK-R from Pettit racing which is a fuel mixture to help lubricate the engines seals.

 

oh dear god

 

when your engine fails a lot of parts will be "not-reusable" cuz of bearing wear.

understand this engine more before you say "no issue with 5w20"

 

either you dont know how to read or you are confused. I never said anything about what you are replying to.

 

It won't hurt but most like to run little thicker, in my opinion.

Change after a couple 1000 maybe. Get some good stuff and just drain that into a pan then take to parts store for recycle. No one (mazda) need to know



Rx8 need change more often than the spec says that 4 sure.

 

either you forgot what you just said or you simply don't know what you're talking about.

 

You are a dumb-***

 

thx.

so do you.

 

woot! more oil threads>@#$^@#$^@$^@#$@$@$^&

 

thanks for those who helped; I read through the oil threads, it was just that the car initially started with 5w20, then swapped to 5w30 & then back to 5w20 today. Kind of threw me off with the things i already read

 

oh my dear god

 

Hell, I think 5w-30 is too light.

 

You're not alone

 

worried? no , are there better choices? yes , does anyone have an actual answer to "what oil should i use"? no , based on your location would 5w-30 be better? yes , could you even step up to 10w-30 in cali seasons? yes

 

holy mother !

 

In the US it is recomended (by Mazda) to use 5w 20 motor oil. As already mentioned this is highly debatable amongst club members. Use the search button because this topic has been beat to death.

 

At some point I'm going to have to write another oil tech thread that gets far deeper into oils that we've gotten before. You'll think very differently about those weight numbers on the bottle as one of the most important aspects of oil and a number that should help you choose which weight oil use use, isn't one that anyone ever pays attention to. Not even on BITOG. Then again like every forum there are probably a few people that know what they are talking about and the rest are parrots who keep blindly repeating what they hear without knowing why.

I will say this about oil weight. With brand A, a 5W20 may be perfectly fine but with brand B a 10W30 may be a better choice and the difference between the 2 has nothing to do with conventional vs synthetic.

BTW: If anyone is curious what viscosity their oil is at any temperature, just ask me. I'll tell you. I've got a nice program here at work that I got from BP/Castrol that draws a viscosity/temperature graph after a couple of simple easy to find variables are entered. It's pretty interesting.

 

You guys are ALL WRONG !

**** ! I mean did u see what Bluerenesis just said? he has no issue! we have to trust his butt dyno ! even he has no idea how this engine works and why 5w20 is garbage for this engine !

Mazda knows best ~~~ BrrWWWwAAAARRRRRRRRRR !

 

well my opinion is that no matter which brand, 5w20 and Xw30 are still too "light" for this engine to use. it might be ok for piston, just not rotary engine.

That's just me tho

 

My owner's manual says 5w20. I've been waiting for the erratum from Mazda, but nothing yet.

The chart in the Australian owner's manual, which shows lots of iol weights depending on ambient temperature (and is not bound by US CAFE requirements), shows 5w20 as suitable for most temperatures. Has anyone gotten the corrected page for that?

Ken

 

Too light where? At what temperature? Here's an example that I'm reading off of the chart tht I just made after entering some numbers. It is for Amsoil 0W20.

At 212*F it's viscosity is 8.97 cSt. At 50 degrees, let's say what it might be at after sitting outside all night on a cool evening, the oil viscosity is 205.31 cSt. On the other side of things, at 248*F, let's say what it's coming out of a hot rotor at, it's viscosity is at 6.2 cSt.

Now let's go to a thicker oil. I'm going to just stick with Amsoil as I have all of their info in front of me. Let's use their 20W50 and the same temperatures. At 50*F it is 576.85 cSt thick. At 212*F it is 18.84 cSt thick and at 248*F it is 8.74 cSt.

Coming out of a hot rotor the difference is a mere 2.5 cSt!!! If you were using this oil and it was a 32*F morning, your oil would have a thickness of 1119.28 cSt! If you want to have some real fun we can compare the exact same weights from other oil companies. Even if the numbers on the bottles are the same, the actual numbers won't be. That's one thing that confuses people.

Keep in mind that the additives in motor oils that protect against wear don't even become active until about 160*F. Another thing to think about is that the maximum temperature of an oil should never be so great that the viscosity is less than a total of 1.77 cSt. Viscosity however isn't the whole story. The viscosity index is one of the most important numbers to know but even then a higher one isn't necessarily better and a lower one isn't necessarily worse. Knowing that number merely tells you what weight as written on the bottle of that particular oil should be used.

You may look at these numbers above and say that "yep thicker is better" but explain why. Then I'd like for someone to explain how the viscosity index plays a part in all of this. When people say all oils aren't created equal, they aren't kidding!

 

My owner's manual and oil cap cite 5w-20. I use 5w-30.

 

8.74cst and 6.2cst may have a difference of 2.5 between them but what's that like percentage wise?
I agree that viscosity isn't everything but it surely plays a role in a high revving engine that is often driven in the higher rpm range.
What's your take on that? You know a lot more than me on the subject so i'd like to see your opinion!