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Good Sunday All!
I researched oil in intake in the forum and found a few threads.
I came across one post in particular that described my problem in nearly the exact same detail.
See the screen shot below.
When I am driving normally around town I am keeping my RPMs under 6K.
I have been checking daily and when I stay under 6K, I get no oil in the resonator box on the intake.
When I get a bit over 6K, my engine hesitates/loses power, I get a burning oil smell for 10-20 seconds or so.
Last time I did this, I checked the resonator box as soon as I got home, and sure enough, I had a couple ounces of oil in there.
Junirol suggested that a PCV kit can be added as done on 2006+ RX-8s.
I can’t find much more than this post mentioning a PCV kit.
Does anyone know anything about a kit like this?
Or does this just mask the symptom of a different problem?
Is this possibly a stuck SSV or clogged CAT?
My OBD2 says my CAT is 1100F when engine fully warm and idling.
Thanks everyone in advance for sharing your knowledge!
Check your oil level, if it is overfilled this might happen.
overfilled my oil, but not much, one day I was doing sprit driving, bouncing around 8k, and I sudddenly got a lot of huge, massive blue smoke coming out of my exhaust with a loud bang. Instantly lose all the power (gas pedal no response). But I shift back to N and back to gear the problem disappeared.
I have the RE oil mod, no cat
Check your oil level, if it is overfilled this might happen.
overfilled my oil, but not much, one day I was doing sprit driving, bouncing around 8k, and I sudddenly got a lot of huge, massive blue smoke coming out of my exhaust with a loud bang. Instantly lose all the power (gas pedal no response). But I shift back to N and back to gear the problem disappeared.
I have the RE oil mod, no cat
It's not your SSV or anything else. Either the oil is over full or you have enough blowby to force oil up the intake through the PCV. A catch can will help keep oil out of the intake, so you don't have to eliminate the root cause.
Thanks for your thoughts Brettus and Zhang.
I have read both of these thoughts in other threads before.
My oil level is below the full mark on the dip stick.
Oil catch can only doesn’t stop the problem it just increases the capacity of oil storage as compared to the resonator box. (See Junirol’s post)
Some say that crank case pressure blow by pushes oil up the fill port and vacuum sucks it into the intake.
Why does this only happen at 6K+ RPM? SSV should be opening around that point; could that be part of the issue?
I have read lots of posts from people who have not had a drop of oil in their intakes so I am sure that there is a fix.
I don’t want to lose power at 6K+ so I am on a quest to find the fix!
Loki,
You mention the PCV...
The post from Junirol indicates the 04 and 05 models were not equipped with a PCV.
06 and beyond had a PCV??? But Mazda released a kit for the 04-05 models? Do you know if this is true?
I asked the Mazda service manager today when I dropped off my car for recall work.
He said he owned 2 RX-8s over the years.
Yet even he had not heard of the PCV kit for the 04-05 models.
The PCV system on an RX-8 consists of a pipe connecting the oil filler pipe and the accordion tube. That's it. If you want it, find an 06~08 RX-8 in a junkyard near you and you can use those.
Personally I'd be curious to know how you have so much blowby for something like this to happen.
It's pretty simple, push more air through the engine = leak more air past the seals = pressurize the crankcase more. Every engine has crankcase ventilation of some sort, the 04-05 ones are just simpler. It doesn't take much to push/pull oil into the intake if you consider that the intake is actively sucking everything in as fast as your engine will let it. You can put the updated 06 PCV system on your 04-05 but it's not required. The root cause doesn't change.
A proper catch can separates oil and gas: gas/air goes in the intake, oil stays in the can. It's not about the holding capacity.
You're right, there is a fix: engine rebuild. The blowby is a symptom of compression escaping past the side seals. But since it's not critical and your only actual symptom is oil in the intake, a $30 catch can is probably a good start?
So I ended up finding TSB 01-050/06 that explains the revised PCV system on 2006+ RX-8s.
Interestingly, the TSB was written for exhaust condensate getting into the oil reservoir.
It identifies the kit as part number N3Y1-13-S80A.
mazdaswag.com offers it for $234 but installing it involves a lot of reconfiguring of the UIM.
Since this is more than I want to get into during summer driving season, it will have to wait...
However, I did find an oil catch can that ended up being a clean and easy install in the meantime.
Conveniently, the REVi intake box has threaded brass Inserts (M6) designed for brackets to hold the engine cover.
Since my RX-8 engine cover was missing from the original owner, I was able to use these holes to mount the catch can.
The holes on the catch can mounting bracket need to be drilled out slightly to accommodate the M6 screws.
Also, one mounting bracket hole needed to be ovaled out to help align to the mounting holes.
Here are a few pictures from the install.
1. Oil in the intake box after about 200 miles and one burp at 6500rpm under load.
2. Oil below the intake box.
3. Catch can mounting to the REVi box
4. Close up before tightening screws
5. Routing of battery cables to avoid rubbing against the catch can (yes, I know I need a hold down bracket).
6. Final routing of hoses (unfortunately the inlet and outlets are on the wrong sides...)
now that the bandaid is installed on the symptom you can start saving for a new engine, which is the real disease/cure of the problem.
sorry that I never saw your thread, been telling everyone this for years and most of the people replying have seen and read them, but nobody mentioned it
never had mine puke even once fwiw, it’s pretty much been a dedicated autox car since 2005 when I bought it
TeamRX8
Thanks for chiming in on this thread.
Yep, I know that day will be coming but the band-aid will do what I need for now.
In researching the issue, I read some threads from 2004 through 2006 where engines with low mileage were already doing the same thing.
But also, like you, I read many people commenting that they have never had the problem with puking oil. (i.e. “catch can on intake?” Started 15-MAY-2006)
Seems like some problem with side seals that Mazda never really got to the root cause.
My engine is a warranty reman with only 60Kish miles on it so I hope to get about 10 more years of enjoyment with it.
I only paid $2500 without a compression test so I’ve can still afford a new engine at some point.
If I ever want to buy another RX-8, when I test drive it, I will push the engine up to 7Krpm under load and test for this before making an offer.
06-14-2020, 01:56 PM
