Will any conventional 5w-20 do?
 

I don't want to start an oil discussion. So, let's just assume I'm going to use factory recommended weighted oil in my 05 '8. So far the oil has been changed regularly by a dealer but I don't know what brand they used. There's no dealer where I live but I have a shop here that I trust. Should I let them use whatever 5w-20 they want to put in it or should I specifify? I don't know what they would normally use for that weight but, in my truck and Jeep they always put Shell 10w-30.

theoretically any oil should do. I'm partial to Castrol GTX

any 5w20 will do. I just prefer castrol gtx.

dont use pennzoil they have a piston on their bottles ...go castrol gtx

I understand I'll need to keep some extra oil to add when it gets low between changes. Would it have to be the same brand they use or just the same weight, etc? If they have Castrol GTX, I'll request that.

Thanks

You can use a different brand of oil then what the shop used, just use the same weight.

as long as the weight is the same, you should be fine.
I usually just take 4 quarts with me if I'm having someone else change the oil. (comes out cheaper that way)

Well I'm taking my truck in first to get it serviced and have the EGR valve replaced. Last week when I went to look at the '8, the check engine light came on and I found the code to mean the EGR sensor had thrown the code. I reset it and it came on again today when we went to pick up the car. So, I'll discuss with them the oil and see what they have or recommend. If they are open to me bringing my own oil, I'll stop buy and get it before I take the car in.

What about filters? Should I be specific about that too?

I like valvoline.. with a k&n filter or oem mazda filter.... or mobil oil filter.. right now i am using royal purple.. its been great for the past 30k miles

I've never seen a shop have issues with a customer bringing their own oil or filters. (as long as the oil bottles are unopened)
as for filters, check out Atkins Rotary. http://www.atkinsrotary.com/store/pr...cat=648&page=1
(those are OE quality filters)

I've always used Valvoline because that's the only 5w-20 oil at Walmart haha. My car still runs.

I have used valvoline,castrol, and pennzoil...i'm partial to castrol....and i've used 5w20, 5w30, and 10w30.....so anyway anything is fine just decide on the weight you want....I use a FRAM filter(I know i'll get flamed for that one probably) but i've never had a problem with them...and when i'm at good old walmart i can get the filter there too!

Great minds think alike.

Motorcraft 5w-20

<-- has 91,000+ miles on original motor

Castrol GTX is about the only thing I can find at retail that actually matches what it says in the manual.

I don't think there'd be a problem mixing something like 5W-20 and 5W-30. It'd end up like 5W-25 so to speak.

Any dino juice will do, but I highly recommend Idemitsu.

However, I don't know that Idemitsu makes a 5w-20 formula.

wolfs head ftw

any disadvantage if use 5w-30?

only advantages

^--The 8 is my first non-turbo rotary. I know 20w-50 would be like molasses in this engine, but what is the best middle ground weight to run in the MSP? 5w-30? 10w-30?

5w30 is popular as its what the rest of the world uses in the 8
i'm thinking of switching to 10w30 soon since i never see colder climates though

As I said, I didn't want to start an oil discussion. However, I was doing random searches on google on this car before I bought it. I remember seeing a thread somewhere where a guy was ranting about there being no reason to use anything but 5w-30 in this engine as that is what the manufacturer recommends in every other country this car is sold except for the USA. I'm taking a stab but wondering if it has something to do with the EPA and exhaust regulations as far as why they recommend 5w-20 here? Either that or something to do with temperature differences here vs. other countries? As you can tell by this thread, I'm not an oil expert. If I can be convinced to go with something other than 5w-20, I will do it. But, can they reject any warranty claims on the motor if they find you've used something other than conventional 5w-20?

I believe they really can't check if it's 5W-20 or 5W-30. As long as you don't tell them, they won't know.

And honestly, don't tell them. I'm going to be using 5W-30 pretty soon, and sticking to that all year, if not higher for the summer months.

Let me know how the 10w30 works out for you. You'll definitely want to let the car get up to operating temperature before driving if you do switch to a heavier weight like that.

I'll eagerly await your report, it's killing me that Idemitsu doesn't make a 5w-20 oil.

Im using 10w30 right now but I'm switching back to 5w30 this week when I change it since i'm moving out of FL and don't feel I need that thick of oil up North....

I use a mixture of Castrol GTX and Mobil 1 whichever is available. Lately I saw some sale on Castrol Syntec so I picked up 2 jugs.

Most FD and TII owners up north run 20w50 in the summer months and 10w30 in the winter months. That'd probably work out nicely in the 8, running 10w30 in summer and 5w30 in winter.

Why not just stick with the 5w30 full stop?!

5W-20… 5W-30… I doubt it's critical. Far more important that you check oil level every other fill up, add oil as necessary, and change it regularly.

My guess is that the 8 has a lower tolerance for forgetting these things than cars powered by ordinary engines. And that 8s that develop engine problems develop them mostly from owner neglect or misuse (i.e. not changing oil regularly, not checking the level frequently, not redlining the engine regularly, modifying the engine, using synthetic oil, dumping additives into the fuel tank).

FWIW, assuming most US RX-8 owners are not on this forum, the vast majority of 8s in this country are running 5W-20.

Among the rest of the recommendations, I'm surprised nobody has mentioned that whatever you use, make sure it's rated API Service SL (or is it SM? check the manual) and/or ILSAC. Look for the API label on the bottle. There are some oils that advertise that they meet or exceed the API rating, but are not actually certified.

Ken

Idemitsu Japan does make 5w-20. but its not their RE(Rotary engine) oil, its listed as motor oil.

in japan they use 0w30 as factory Rotary fill, of course its Synthetic (no conventional oil can go 0w)

and Mazda Japan sells Synthetic motor oil thats PAO based, probably Idemitsu rebrand.

the clearance for 13b-msp is tighter, but heavier oil will flow just fine.

Im a maintenance freak and my motor still failed, 0-5K miles 5w20, 5K - probably 48303 miles 5w30. and dont forget, your motor might be dying and it will run just fine till it dies one day.