Wow, can this soap opera get any better? Introducing a synthetic oil flame war into this thread now :D

 

heheheheheheehe popcorn please

 

Not so fast there cowboy!! We only have one oil cooler on our cars (high and std power). We also get 100deg plus days down here for a stretch at a time. We've yet to see this problem rear it's head down here.....albeit we only have a few thousand RX-8's in Australia.

 

I guess the old thermostatic rad fan clutches on the 12A RX-7s were smarter than they looked. I remember that in high ambient conditions, the fan ran (noisily) almost all the time. Since the oil cooler was mounted right below the rad, that probably kept the oil a lot cooler, regardless of water temp. In the 8, the fans apparently switch on under high water temp conditions, and do not in any case pull air through the oil coolers. Oil does a lot more heat transfer (engine cooling) in a rotary than in a boinger.

So maybe the answers are better oil (not getting into the synthetic debate) and possibly an aftermarket fan setup for the oil coolers. I know I went to engineering school for something...

Oh yeah, and keep the revs up! It's a rotary after all...

 

yes i was thinking that- but i believe you use a different weight oil down under

 

What kind of temp does it take to break down the 5w20?

I think we have a BINGO here.

 

I actually was concerned about the same thing. Why are the single oil cooler cars in Australia not having any issues? We all know that it gets hot in parts down there.

I personally don't see this as an oil weight issue. Oil formulation may play some role such as how fast an oil will break down when heated but it shouldn't be weight based to the same extent that it would be between different oil companies or synthetic vs nonsynthetics.

I still want to know, on cars with only 1 oil cooler, what are your oil and coolant temps when you are driving in hot weather? If the oil is hot, the coolant will be hot and vice versa.

 

I also think part of the problem is the light weight oil. I live in south Florida (Palm Beach County) and its 90++ every day. I have always run 20w-50weight oil in my 8. Car is also tracked and after adding a oil temperature guage I was shocked at how hot it ran - 245 to 250 degrees. After seeing that I switched to 20w-50 Valvoline Racing and did a quick fix to help lower temps by cuting open the two lower grooves in the inner fender cover to allow more air out from behind the oil coolers. This took the track temperature down to 235 to 240. Normal driving without traffic is at 180. As soon as I hit traffic, it will go up to 210 to 220. These temperatures are too hot for 5w-20

Jay Goldfarb
2004 RX-8
35,000 miles

 

Hello Jay

interesting info on the oil theory.

thanks for the info

I need to check and see what type of oil I had in my 8

pretty sure it was 5-20

whatever the dealer was recommending, and 5-20 sounds familiar.

Maybe we are onto something here.....


Rob in Vegas

 

I suspect your temperature drop had more to do with the ducting than anything.

Are you saying that you have seen oil temps up at 250*F??? Holy crap!!! That is unheard of and downright scary!

Under no circumstances should the oil temperature in a rotary EVER get above 210*F. This is asking for failure. I don't care what weight oil you run, it will break down quickly above this. The car needs ALOT more oil cooling. This is just dangerous. I don't know if I can get the point across how absolutely disturbed by this I am. This is extremely serious and will greatly affect the longevity of the engine. I am scared for every RX-8 owner at this point. This needs to be addressed whether it be through Mazda or on your own. This really explains the engine failures in hot climates. Everyone regardless of engine type, please log your oil temps. This is not acceptable and should not be ignored.

 

Rotarygod

what is the easiest way to track oil temps?

is there a fairly inexpensive devicde that I could buy to do this?

I would be happy to track my oil temps and report back once I get my 8 back

Rob in Vegas

 

Synthetic oil does not "break down" at 250'
In Europe they use synthetic oil in RX-8 at the dealers.

 

I have a Scanalyzer & will be checking it out this weekend. MT tho......

Dang, that's the 1st time I was sad NOT to have the AT.

 

Gotta say that the 3rd gens that Speedsource ran in Speedvision Cup ( and won the championship with) ran higher oil temps than that ( closer to 275-290 according to them) I was told that when the temps climbed they used oil temp as the tach meaning as it went up, the revs came down. We saw some pretty high temps in the 2nd gen ITS cars early on but got them down to 180-200 w/ducting and even bigger coolers. Bottom line, the guts of the engine bearings and such were not damaged when inspected at teardown but performance certainly was not as good.

I agree that lower temps are more desireable but high temps are not as big a killer as you make them out to be. I was scared shitless when we saw the temps the ITS cars ran but we ran up front for several seasons w/no engine failures thanks to Dr Ianetti and Roger Mandeville. My FC turbo w/MoTeC datalogged oil and water temps of 185-210 deg F in August in Atlanta traffic. Under boost at just shy of 370 rwhp @ 12 psi it would climb 10 deg. The engine has been alive and kickin since 2000 but now lives in a Formula D first gen.

Hope I didn't take up too much space!

 

Guess this problem is not unique to my Mazda6s. Maybe Mazda like high oil temps for some reason.

The Mazda6s, while not a rotary, holds its' oil at about 210 degrees constantly when at idle, goes up to about 225 when driving, and it can easily get over 250 degrees when driving aggressively more than about 10 minutes. And that's at relatively mild ambient temperatures.

 

these engines dont have any thanks to give to Dr. Ianetti unfortunatly.

 

If the oil was hot enough to break down, wouldn't the temp guage be pegged? I really dont know what temps oil breaks down at, but it just seems that if it was hot enough for the oil to break down that the check engine warning would have come on.

 

You can't really compare race oil temps to that of a street car. Most race cars will change their oil fairly often. Street cars don't from a mileage standpoint. These high oil temps after many street miles will prove far more harmful than high temps on a far less track miles. If you look at the most serious of rotary race cars, say the 787b, you'll see that the oil cooler was nearly as large as the radiator. In a perfect world it should be. The oil expels nearly the amount of heat that the coolant system does.

 

If these problematic cars are all in Vegas, is it possible it's some isolated manufacturing or assembly defect that happened to a specific run of cars at the factory? And those cars ended up on the same boat headed to Vegas? How close are the serial#s on these cars? Were all the cars bought in Vegas or were some from another state?

The oil and temp thing sounds interesting but like somebody else said, there are plenty of hot places other than Vegas.

 

Highly doubtful.

A single boat doesn't head to Vegas. A single boat brings all the RX-8s for X weeks to the Port, and from there they're diveded out amongst the allocation that the dealer requested. The chance of a particular sequence of them built at a particular time all ending up in the same location is extremely unlikely.

 

The Speedsource folks stated last Saturday they are using 20W50, if I remember correctly.

I have been in the habit of using 5W30 (like Australia & Europe are told to use), and changing my oil every 2500 miles. Certainly feel more comfortable with the 30w than the 20w.

 

we first heard of the issue from Mazdaspeedgirl a few months ago when she informed us that her dealer service in Lubbock Texas had replaced 6 engiens already. Thatturned into a dozen in a couple of weeks and another dozen in a nearby city. Phoenix and areas around there as well plus a smattering around the country.

 

While there are certainly hotter places in the nation, Las Vegas is probably the hottest place most likely to have a significant number of RX-8s in one spot. A handful here and there we wouldn't know about, but 30 all at once we hear about.

And this year has been unbelievably hot. I work for a railroad and was down in Needles, CA a couple weeks ago. It was 129 degrees and 150 degrees around the locomotives. Our locomotives were dropping like flies for much the exact same reasons that the RX-8 was -- they run at high revs (for them high is 900, not 9000 ) without moving quickly enough and the cooling systems in place just couldn't keep up and they were overheating the engines and the electronics.

So don't feel too special. Gigantic American diesels are suffering from the same problems as the rotary.

 

How do you increase the air flow to a locomotive?

How do you move air across the coolers on this car at idle?

 

drive the locomotive over a really tall cliff.