RX-8 basics

I've got a friend who just bought an '05 RX-8. I'm a Miata guy and I don't speak magic spinning triangles. What are the basic need to knows on these? All input appreciated.

THanks, y'all.

Keep the oil topped up, redline often

Forgot to mention - he checked the oil and said it looked "foamy". No water in oil, just foamy.

uh-oh. you said "RX-8" on GRM.

-running the engine to redline is important to keep it clean. (it's fun, too).

-let it warm up before shutting it off. this will avoid flooding. the rotary injects extra fuel when the engine is cold to aid in startup; shutting the engine down while cold can leave the extra fuel in the engine. if it does flood, the easiest way to deal with it is to just keep cranking. 10 seconds with the accelerator floored, 10 seconds with it up. repeat. best to jump the battery b/c it could take a long time, but the car will eventually work it out. if it needs to be shut down cold, hold the engine at ~5000rpm for ~15 seconds, then shut down the car and release the pedal simultaneously. the engine will run for a few seconds and will burn off the excess fuel.

-use good gas. use good oil.

-there are a few well-known (minor) problem areas, like poor soldered connections on the HVAC temp control; check rx8club.com or http://www.finishlineperformance.com/store/pages.php?pageid=11 (for RX-8 TSBs).

-the taillights can collect water; if so, redesigned gaskets are available and easy to install.

-enjoy the hell out of it. it's a great car.

edit: "foamy", huh? like milky? was the engine cold when he checked it? if so, might just be condensate: http://www.finishlineperformance.com/pdf/rx8/bulletin/01-050-06-1664.pdf

The oil on my dipstick looks "foamy" once my car is warmed up. Not milky though. The oil looks fine every time I do a change.

Keep an extra quart of oil in the trunk, and check it every 3-4 fill ups.

I've owned mine for three years and love every moment of it.

Dorsai wrote: Forgot to mention - he checked the oil and said it looked "foamy". No water in oil, just foamy.

I pondered the RX8 for about the length of time it took to read the issues (about 3 or 4 forums) with earlier 'foamy' oil in engines, flooded restarts, high rev oil consumption and the such.

Wont be going there as it seems these issues/headaches are just part of the joy of RX8 ownership. I need newish car to be DD if its in autoX stock classes, and DD reliability is is lacking without unusual amounts of care and feeding for a ~5 year old car.

Good luck and check the RX-friendly forums for more issues and happiness!

Eric G

The oil in all my cars has bubbles in it when i check it if they've been running for any length of time... i don't think that would be a big problem.

i never noticed any bubbles or anything...not to say they weren't there, but nothing that struck me as any different from any other oil i've seen in any other engine.

FWIW, i think the "care and feeding issues" are overblown, esp for anyone who practices regular car maintenance. it's too bad.

being careful about not flooding it is the only real consideration, and the only time i had an issue with it was b/c A) it was 15 degrees out when i shut it off immediately after starting, and B) i don't have the upgraded (2006+) battery and starter.

even the oil consumption in daily driving is next to negligible (it's designed to use ~1 qt every 10,000 miles)...you might be adding a cup in between 3000 mile oil changes. regular autoXing or track days might accelerate that usage slightly, but at worst it's another 45-60 seconds added onto every third gas station stop.

other issues are no different than most any ~5 year old car.

as a dual purpose DD/autoXer, i can't think of a better choice.

I think the oil consumption of an RX8 would be an improvement over at least 2 of my cars.... And the 3rd one uses more PS fluid than the RX8 does oil, so i certainly wouldn't be mad.

Mine never has foamy/bubbly oil either, whether hot/cold or after sitting/coming off 30min+ track sessions.

Mine does use more than a quart in 10k miles of ordinary driving though. Mine is closer to a quart in 3k (slightly less than that). I'd be surprised if it's designed consumption is as low as 1qt/10k, as the manual suggests checking the oil level at every other fill-up. At 1qt/10k, you'd change the oil before you needed to add any.

On balance, I'd rather it burn more oil than less. Oil is cheaper than apex seals.

Everyone else has hit the high points except for the usual bitching about the fuel economy. I will state again that mine reaches the old EPA hwy number (24) on road trips. Queue bitching from the naysayers in 3, 2, 1....

I was told the foam you speak of on the dipstick is caused by condensation is the tube itself. The oil shouldn't be foamy but if it has foam on the dipstick then not a big deal. At least that's what all the local spinning triangle guys tell us about our RX8.

Get used to 15mpg?

The condensation in the oil isn't just an RX-8 thing, I've had a few RX-7's do it too. I never did pin the cause down.

Everyone else has hit the high points except for the usual bitching about the fuel economy. I will state again that mine reaches the old EPA hwy number (24) on road trips. Queue bitching from the naysayers in 3, 2, 1....

Per Schroeder wrote: Get used to 15mpg?

The GRM forums have rightfully balanced themselves, carry on

billy3esq wrote: Mine does use more than a quart in 10k miles of ordinary driving though. Mine is closer to a quart in 3k (slightly less than that). I'd be surprised if it's designed consumption is as low as 1qt/10k, as the manual suggests checking the oil level at every other fill-up. At 1qt/10k, you'd change the oil before you needed to add any.

Most of the owners manuals I have that have come with cars say to check it every fill up. And that's in cars not designed to use basically any. Pretty sure that that's mainly a CYA move (but still not a bad idea in something that actually does use some on purpose).

Not saying it does or doesn't use more than 1qt/10k, just that that line in the manual doesn't really seem to be necessarily related.

The line in the manual is expressly related to the designed consumption:

1st Paragraph on Page 8-12 of 2005 RX-8 Manual The Mazda RX-8 requires regular checking of the engine oil level. The compact, high performance RENESIS rotary engine in your vehicle consumes a small amount of engine oil due to its structural design.... Mazda recommends checking the oil level at every second fuel filling.

One qt/10k is not uncommon on conventional engines and is less than the acceptable level tolerance over two oil change cycles. (The RX-8 has three 1/2qt marks on the dipstick between "Full" and "Add" and has 7.5k normal/5k severe oil change intervals.) Because of these two facts, I doubt they would specifically refer to the consumption in recommending periodic checking if it were really designed to only use 1qt/10k. They would just include the normal warning like what your manuals have.

Moreover, I don't know anyone who's using that little oil in normal driving, which suggests that if 1qt/10k was their design target they really blew it.

Finally, 1qt/10k just seems too low when you consider what's going on. Virtually all the oil used to lubricate the apex seals is going to go out the tailpipe. I'm not a lubrication engineer, but that just doesn't seem like enough to me.

billy3esq wrote: Finally, 1qt/10k just seems too low when you consider what's going on. Virtually all the oil used to lubricate the apex seals is going to go out the tailpipe. I'm not a lubrication engineer, but that just doesn't seem like enough to me.

Oh I agree there. 1qt/10k seems pretty low to me to accomplish anything. But like you, it's not really a field I really know enough about. That's just a "gut feeling" type thing.

Whether it's written related to consumption or not, that same interval is recommended in cars that aren't designed to use oil. So I don't think that it's presence even with that context has much to say about the actual rate other than "hey your car uses oil on purpose, so don't forget to check it".

Again, I'm not saying that it uses anything like that small an amount. Just that the wording in the manual doesn't really add anything useful to estimating the rate it's used.

EDIT: In fact, I'll go so far as to say it intentionally says nothing about the usage rate because the rate used is obviously going to vary with just how you put those miles on, and picking a # is just asking for complacency

Me, I'd likely check it every time, since it's not that much more often than I check every car. I check most of my cars every few fill ups anyhow. Not that they are using oil (this may be the first time in my life not a single car in the "fleet" isn't burning/leaking oil in any noticeable quantity), but if they suddenly started to in a non-obvious way, I'd sure like to know about it sooner rather than later. As a bonus, you get a look at what the oil looks like which might give you a heads up re: some other issue (signs of coolant for example).

keethrax wrote: Whether it's written related to consumption or not, that same interval is recommended in cars that aren't designed to use oil. So I don't think that it's presence even with that context has much to say about the actual rate other than "hey your car uses oil on purpose, so don't forget to check it".

We'll just have to disagree. I think the specificity of the context leads to a reasonable inference that the designed rate is higher than (1) something that would be not be considered abnormal usage in a piston engine and (2) something that would be masked by the oil change intervals anyhow.

Perhaps my background makes me more willing to draw reasonable inferences from limited facts.

keethrax wrote: EDIT: In fact, I'll go so far as to say it *intentionally* says nothing about the usage rate because the rate used is obviously going to vary with just how you put those miles on, and picking a # is just asking for complacency

That's what's in the ellipsis of my quote. I don't have the manual in front of me any more, but it says something to the effect that it can vary based on engine loading, etc.

In practice, my car uses much more than the supposed 1qt/10k (which I've never heard before this thread) in track driving. I see around 1/2 qt/hr in track usage, which is a little high compared to other track-going RX-8s I see. I try to keep it within 1qt of full, which means that I pretty much have to add oil when I need gas.

keethrax wrote: Me, I'd likely check it every time, since it's not that much more often than I check every car. I check most of my cars every few fill ups anyhow. Not that they are using oil ..., but if they suddenly started to in a non-obvious way, I'd sure like to know about it sooner rather than later. As a bonus, you get a look at what the oil looks like which might give you a heads up re: some other issue (signs of coolant for example).

Every fill up would be overkill. You'd wipe more off the dipstick than gets burned. If you've got coolant in the oil on a rotary you've got huge problems already.

I check the RX every 2-3 fill-ups, at the beginning of a track day, and after every track session (typically 1/2hr). For every other car I've ever owned, I check it when I buy it, at the first fill-up, then the third, and so on until I get to either: (1) about half-way through the change interval or (2) the interval where it's using about half a quart. I then check it at that interval until the usage goes up, at which point I adjust accordingly. I've never found oil below the add level on the dipstick using that approach.

I haven't had a car that uses any oil between changes (other than the RX-8) for about 6 years now, so the rest of the fleet gets the roughly half way through the change interval treatment.

In reply to bamalama:

Piston engine airplanes get it. It looks like light colored peanut butter. I have never heard of it hurting anything.

Foamy oil is not normal. There is an update to the pcv system on 04-06 models. Check for service bulletins. The bulletin includes a new upper intake and new vacumn lines for the pcv system. Also find out if the ignitikon coils have been replace recently. Known for arcing to the plate that they are mounted to and can make for hard starting during the winter or summer for that matter.