StratoMike

Hey guys, Just wanted some advice on what kind of oil to get and the best place to get it from for my RX8.

The manual says that it needs 5-40 but I cant find any
So Im wondering if there is a grade higher and if there is how would I recognise it?

e.g is 10-40 better than 5-40?

Thanks in advance for the help.

Im_DANomite

iTrader: (1)

0W-20 hoss...i use Castrol. you'll find it at any auto store.

Gomez

Mazda Australia recommend 5W-30. They sell oil specially formulated for the Rotary at the dealership. About $50 for five litres.

Page 8-16 of your owners manual refers. Pick anything that suits your operating conditions.

Gomez.

StratoMike

ok , so is it a safe assumption to say that the lower the number the better?
Im a bit of a noob I know :-)

BVD

No, not necessarily, it depends on where you live. :D

Oil is rated with a number that indicates its viscosity (which refers to the thickness or "flowability" of the oil).

Oil has to be thin enough to flow round the engine efficiently when it's cold, but also thick enough to still do its job when it heats up and gets thinner. Depending on the local climate, cars need differently rated oils to cope with the temperatures they'll be working in.

Most commonly used motor oils are "multigrade" which means that they contain additives that allow them to flow better when cold, but also retain more thickness when hot.

The lower figure (i.e. 10W - where the W stands for winter) indicates the performance when cold, and the higher figure refers to its performance at a hundred degrees.

For more information, either read your owners manual as Gomez suggested (there's a chunk of info showing which oil relates to which climate) or do a Google search on viscosity and motor oil.

Here's a start:

http://auto.howstuffworks.com/question164.htm

Good luck.

takahashi

I wonder if my car is subjected to 4 track days in the next 6 months... if I need a higher rating oil such as 5W50 rather than 30... but finally decided that I am changing oil that frequently that it is a waste of money to pay for $100/5L of oil like the redline.

BTW I have not change my oil for the last 4000km... I am a very bad boy
On the other hand, I have only been around town for the last 4000

Hymee

iTrader: (1)

I needed oil in a hurry the other night.

I decided some oil was better than no oil.

So I put something in that was somewhere on the "chart" Gomez listed.

Cheers,
Hymee.

labrat

Taka, I presume you use a fair bit of oil during your track sessions and have to top up with quite a lot of new stuff. If this is so, then the average "age" of the oil in your sump is likely to be much less than for those of us who putter around town using say 200mL every 1000km. So in this respect, having done 4000km since the last change mightn't be so tragic. You can get a very rough idea of how the oil is faring by checking the amount of "soot" (black stuff) in the oil when you wipe the dipstick on the paper towel.

I must confess that since my dealer has been using Castrol synthetic at my oil changes, I've been topping up with the same stuff. I guess as long as it doesn't get stuck into the end seals, I would prefer a synthetic due to its generally superior properties.

takahashi

I see your logic. And I think you are right. I don't see much "soot" at the dipstick. Just oil stain on the rug.

takahashi

Kalli

Where did you get your oil that is so cheap. Everywhere else is selling at $55

StratoMike

Thanks guys,I went out and got some 5w-50 and it said its recommended for Ferraris etc.
I know a Ferrari isnt a patch on an RX8 :-) but hey,any port in a storm.hehee.Thanks also to BVD for the link and the explanation.

kiwimeat

And was 10% GST included or at the bottom of the invoice? That probably explains the price differential.

My latest oil purchase no longer has Mazda label, it's a Castrol bottle. Anyone else the same?

timbo

I've tried to bite my tongue.....

So it's now Castrol 5W-30 mineral oil -- wonder if Castrol stock it?

Gomez

My first purchase of this oil mid last year came in a Castrol container. It is imported in bulk and decantered here. Maybe Castrol sold the empty containers cheap. I have no idea who makes this oil. My recent purchases don't have Castrol embossed on the container. Here's a pic of the old one.....

Gomez.

sco

I'm getting my RX-8 serviced tomorrow - I'll see what 710 packs they've got..

(you know... stuff to put in where the 710 cap is) :p

Gomez

Mazda 710 avail in 57 and 17 containers. The 17 is more than a fifth of the cost of the 57, though.

xxup

True, but it does fit nicely in that lockable pocket between the rear seats..

In 3,000+ kms I have only just reached the first dot on the dipstick..

Gomez

That's true. Actually, I'm going to stop lugging it around. I never use it. I go through, I dunno, about 1.5 litres every 10,000 K's? Bugger all. I only check it every 3-4000K's.

auzoom

I got bored...this is my summary for those that care:

The viscosity of Motor Oil is generaly measured in centistoke (cSt), this a measurement of somethings resistance to flow. The lower the number the less viscous (resistant to flow) it is.

The numbers used in Motor Oil ratings are the "weight" of the oil. These "weights" are an arbitrary number assigned by the SAE (Society of Automotive Engineers).

The SAE assigns a weight based on the viscosity of an oil @ 100C (212F). Crank Case Oils that rate between ~4 & ~6 cSt have a weight of 10. Between ~6 and ~10 cSt a weight of 20, etc.

Now remembering that the weight of an oil is its viscosity at 100C and that oil gets less viscous (resistant to flow) as it heats up, you can hopefully see why we need two measurements. One for when the oil is hot (100C) and one for when the oil is cold (Rated at 0F...yes F, ie -17.8C).

So a 10W-40 Oil will behave like a 10 weight oil at 0F and like a 40 weight oil at 100C.

I used this page to get my information http://www.repairfaq.org/filipg/AUTO/F_oil_facts.html and I think the best sentence to R&D (rip off and duplicate) is the following:

Multi viscosity oils are one of the great improvements in oils, but they should be chosen wisely. Always use a multi grade with the narrowest span of viscosity that is appropriate for the temperatures you are going to encounter. In the winter base your decision on the lowest temperature you will encounter, in the summer, the highest temperature you expect. The polymers can shear and burn forming deposits that can cause ring sticking and other problems. 10W-40 and 5W-30 require a lot of polymers (synthetics excluded) to achieve that range. This has caused problems in diesel engines, but fewer polymers are better for all engines. The wide viscosity range oils, in general, are more prone to viscosity and thermal breakdown due to the high polymer content. It is the oil that lubricates, not the additives. Oils that can do their job with the fewest additives are the best.

Hope that helps.

Andrew

auzoom

ohh...and fwiw, i use Castrol Formula R Synthetic 5W-30.

Andrew

sco

Gomez,

5710 aint 5710

:p

sco