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RX-8 Rotary Problems

 
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mproleik



Joined: 12 Jul 2005
Posts: 2

PostPosted: Tue Jul 12, 2005 7:54 pm    Post subject: RX-8 Rotary Problems Reply with quote

i have a 2004 rx-8 with about 8k miles on it. i recently had the oil light come on... i checked the oil level (with the engine cool) and the level was high. Before i could get it to the dealer to have this checked out, the engined overheated on a hot Florida day and coolant leaked all over the parking lot. I had it towed to the dealer immediately. They have had it for about a week now. I am very concerned about the engine being brought back to "new" condition. They are telling me that the oil level was low and that's why the oil light was on. I know for damn sure that when i checked the oil level days earlier it was actually past full. This is very irritating... Evil or Very Mad I'm not an idiot... i have a Mechanical Engineering Degree and i've taken apart my share of engines. Now for my questions Question What could have happened to the engine that caused the oil level to rise over time? Could the overheating have caused some of the oil to burn off? Could there be permanent damage to my engine? What technical questions should i ask the service manager to assure that the problem has been fixed? Sorry for so many questions... any help would be greatly appreciated Smile
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Blake
Been there, done that


Joined: 12 Jul 2005
Posts: 135
Location: Portland, OR

PostPosted: Tue Jul 12, 2005 9:48 pm    Post subject: Reply with quote

I wish I could be more help on this one, but my experience with RX-8s is limited. One thing that I can think of off hand that would cause the oil level to rise is dilution, which in a rotary is usually caused by fuel (as opposed to, say, coolant). Fuel dilution occurs from fuel working past the oil control rings and is most prevalent on turbo cars, where the intake charge is under pressure and the combustion pressure similarly higher. And, of course, flooding any engine can lead to fuel dilution of the oil. Mazda actually added a new "cut off" seal around the oil control rings that I believe was intended to add a bit more protection, but I don't know how effective that has proven.

Fuel in the oil is a Very Bad Thing (TM) as fuel is a solvent, consequently breaking down the lubricity of the oil. Many turbo rotary owners change oil more frequently that the usual 3,000 miles, but non-turbo owners don't seem to suffer the dilution problems unless their cars flood often (poor compression engines or 2nd gen (FC) owners who shut off their cars before they are fully warmed up due to a quirk of the EFI). Note: If you do flood the car, it's usually best to get an oil change ASAP, just to be safe.

When you get serious fuel dilution, you can smell the fuel in the oil. You may also notice the oil does not feel so "slick" between your fingers.

Again, that's just speculation based on your description of the oil level rising. Just a possibility. The more serious concern with any case of overheating is the damage it can do to the engine. Rotary engines are particularly suceptable to warpage due to the large, flat plates that form the sandwich contruction...they have a lot of contact area. You don't need to be paranoid; just be careful. The biggest factor in warped rotarys is that the factory gauges traditionally have a dead zone around the "normal" area, so that any range of temperatures that Mazda deems normal do not inadvertantly alarm the car owner by creeping toward the red mark. Very thoughtful of them to keep us from worrying like that, but when the car does overheat, the gauge seems to go from perfectly "normal" to burrying the needle in the red in a blink of the eye. If you are not actually watching it, you might not notice the warning until steam is pouring out from under the hood. Still, you have to really cook it to warp the plates but, once you do it, the engine is toast. Don't let that keep you up at nights, however. The symptoms would appear right away.

Would overheating cause the oil level to fall? Possible, but unlikely, I would say. What to ask? Ask if there is fuel in the oil and perhaps even ask to smell and feel it yourself. Permanent damage? Again, it's possible, but hopefully it was just a mild overheating. But, if the oil was truly low (not just the 1-quart, where the oil light usually comes on), you could have starved the oiling system. That is really bad. Insist on a compression test and a cooling system pressure test.

My specific advice is: if it's covered under warantee, don't sweat it. Smile If not, then don't trust the Mazda service people farther than you can throw them. Mazda mechanics in the last ten years or so tend to have little or no rotary experience and some dealerships seem to have a REALLY bad reputation. Mazda cracked down a couple years ago, I heard, but I have no idea if that helped. Most rotary owners use independent shops for all their service and engine work. While those are equally spotty in reputation, some are quite better than the rest. Most of those better shops seem to be owned or employ former Mazda mechanics from back in the heyday (mid 70s-late 80s). RX-8s tend to still be under warantee, so not many have made their way into the independent shops. Still, if they are saying it was your fault and are responsible for the expense, go to an independant shop with a known reputation for a second opinion and the actual work required. Just my opinion.

Again, I wish I could offer you better advice. Unfortunately, I can only speculate. I will talk to Rob Golden, Pineapple Racing's owner and engine builder, tomorrow and see if he can offer more expert advice.
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Blake Qualley
Pineapple Racing, Inc.
(503) 233-3878
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Blake
Been there, done that


Joined: 12 Jul 2005
Posts: 135
Location: Portland, OR

PostPosted: Thu Jul 14, 2005 1:09 pm    Post subject: Reply with quote

I talked with Rob, here at Pineapple Racing, and he had more questions than answers. How long was it between the oil light coming on and the overheating? Has the dealer already drained the oil and perhaps cut open the filter to look for contamination? How high was the oil...a little above the "full" mark or really high? When they said it was low, how low was it? Did the oil pressure gauge show a low reading at any point? Was your AC on when the overheating occurred? Did the overheat light come on and/or did you actually see coolant steaming out, or did it just come out of the overflow bottle? If the latter, the overflow bottle just might have been overfilled!

It doesn't really seem, at first blush, that the overheating and oil level issues are necessarily related. Oil does consitute a good deal of the cooling capacity, so being a bit low with such a small oil capacity to begin with, could make the difference, but it's unlikely. After looking in the Mazda Workshop Manual and Service Highlight books for the RX-8, I can't say I learned much -- They ought to call them the Mazda "How to read the onboard diagnostics system" Manuals as they contain little else. Just trying to see if the RX-8 had a separate gauge for oil level and oil pressure was damn near impossible, looking at those books. We finally found a drawing of the instrument cluster burried in the Service Highlights book.
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Blake Qualley
Pineapple Racing, Inc.
(503) 233-3878
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mproleik



Joined: 12 Jul 2005
Posts: 2

PostPosted: Sat Jul 16, 2005 12:14 pm    Post subject: Reply with quote

i just got the car back from the mazda dealer... given all the questions i have, do you mind if i call you to discuss in more detail? If so, when is a good time to reach you? .... thanks for all your help! Smile
Mike
Palm Harbor, FL
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Blake
Been there, done that


Joined: 12 Jul 2005
Posts: 135
Location: Portland, OR

PostPosted: Sat Jul 16, 2005 1:56 pm    Post subject: Reply with quote

Call us on Monday, sometime during the day. If you can't get through, please be patient and try again. We get a lot of tech support calls, despite the fact that few of those calls are from paying customers. It can be frustrating for us, sometimes, because we are trying to get paying work done and keep the phones open for our real customers, but if you are respectful of our time we don't mind spending a few minutes helping you out. Rob is really the one you want to talk to, but he is also the busiest...just keep that in mind.
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Pineapple Racing, Inc.
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are100



Joined: 21 Jul 2005
Posts: 1

PostPosted: Thu Jul 21, 2005 4:33 am    Post subject: Reply with quote

There is currently a recall going on in the US about an overheating problem, but I believe it isn't to do with the Engine, its more Catalytic convertor. http://www.rx8club.com/showthread.php?t=66002

Are you familiar with Rotary engines? if not a few days is irrelevant, its more the amount of miles you have done and how hard you have driven.

The rotary engine spuirts a small amount of oil into the engine to help lubricate the seals. I drive my 8 hard and have to add about 500ml of oil every 2 tanks of fuel to keep it between half and full.

Andrew
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