I went in for my first oil change last week at the dealer. The "lead service tech" did the oil change and put in 10w30. I would expect the "lead tech" to either be familiar with the specs for Mazda cars or at least read the manual, which clearly shows 5w20. So ... is it going to be a big deal with the heavier weight? I'm not sure if they chose that weight because of Houston's heat. Should I make sure to request 5w20 in the future?

 

well I see you live in texas. I live in florida, and in hotter climates like ours oil tends to break down faster. Ask the dealership and the'll probably use that as justification. If it really concerns you take it back and have them drain the 10w-30 out and replace it with what the manual calls for. Consider this though........In my 94 rx7 I used 20w-50 castrol GTX. Do you think the owners manual called for oil that heavy? I doubt it.

 

I'm going in for my 8's first oil change on friday and am bringing my own oil (dealer said it was okay) Castrol GTX 5-20.

 

Draining will only remove 3 quarts or so? Doesn't the rx-8 hold over 7 quarts? The two weights were mixed so you after draining you'll end up with a mix of of 5-20 and 10-30 still left in the oil coolers.

 

One thing I forgot to mention ... before the oil change, I got the intermittent oil light. After the change, I haven't seen the light come on. Would the heavier oil negate the oil pan problems?

 

Interesting theory...

 

I think heavier oil would cause a oil starvation in a engine that is designed to burn oil. It would reduce the amount.

Mazda spent thousands of hours designing the engine. I would follow the Owners Manual and not second guess or Monday morning quarterback the engineers.

my .02 yen

 

Weight won't make a difference.
Thin oil is USA/API/treehugger mandated BS. Mazda bent over for a miniscule improvement in MPG.

Thicker oil won't foam/aerate as bad as the thin oil. It'll also take the heat better. The MOP/injector doesn't care what it sees. It is a low volume displacement pump and will pump the same regardless of weight.

 

closer to 5 quarts. And the dealership isn't going to flush the oil coolers with every change, so the oil is already mixed.

 

Does it really hold around 7 qts? According to the manual, with oil filter 3.7 qts. The oil pan is very shallow, so where could the 3 + qts be stored?

 

Probably a quart in each of the oil coolers plus all the oil lines between them. You gotta watch the dealers Mine put to much oil in as others have seen. So check your oil after its changed.

 

Correct. RX-8's in Europe and Japan do not spec 5w-20.. I don't even think they sell such weight over there, it's only sold in North America for CAFE requirements.

 

don't forget too that north america spec cars have two oil coolers, and the J-Spec ones mostly (all??) have only one... euro, i have no idea.

 

I arranged for my first oil change today- I asked the service advisor what grade oil they use - he said " umm 10w30 ---- or whatever it calls for"
I guess I'll school them when I bring it in.
I also asked yesterday if they were aware of the oil pan baffle problem as my car is one of the ones with the oil light irregularity.
So far he has not been able to retrieve any info from Mazda about the problem. I think I'll print out some forum threads to show him Monday when I bring it in.
He did say they had a man who was responsible for rx-8's and he has been to some kind of school on them.
I've been driving really dependable Honda's (Civic, Accord, Prelude, Civic Si) for 23 years before this car and had a terrific service shop to go to. I hope this Mazda shop turns out to be dependable too.

 

Just had my oil changed by Tom Bush Mazda in Jacksonville, FL. They used Castrol 5w-30. I just passed 3,000 miles.

 

my .02c. My first change, they didn't know what they tech had put in. Even though the cap says 5/20. As a courtesy [I picked it up the following day because of the flat tire ordeal] they drained it, refilled w/5W20, ran it, drained it, added 5/20 again. And I think one more time. That's one problem/concern I always have about using a dealer (or any garage for that matter) -they will never treat my car the way I do. When I change it, I clean the filter base off very well, let it drain fully, add oil to the new filter before installing, etc. It's just a job, and it's just 'another car' to most techs.

 

Took mine to the local dealer (not where I bought the car) for first oil change this morning and they used 5w-20. They charged $65.00 for the oil change! I'm glad Mazda's picking up the tab. I asked why so expensive, and they said because they checked and the car requires a "synthetic blend." They also charged $33.00 for labor.

Does this sound strange to anyone but me? And, forgive my ignorance, but I thought the RX-8 requires regular motor oil. So, what is the difference between "synthetic" and "synthetic blend"? Wonder why they didn't just use regular oil. Will what they used hurt my car?

Thanks for the help!

 

That's BS. I don't believe the manual indicates anywhere that the RX-8 "requires" synthetic blend.

From all the threads in this forum on this topic, I believe you will be OK with synth, synth/blends, or dino.

 

Thanks jonalan. I did go back and search through those posts and feel much better about it.

It'll be interesting to see what they charge next time I take it in. I can't imagine Mazda's going to be thrilled about getting a $65 oil change bill.