max5roadster

Took my 8 in for a rough idle (i.e. vibration) I mentioned in a previous thread. Well, the service guy came back and asked if I used synth oil, which I have used Royal Purple 5-30 for the last 5k or so. (Changed twiced) Once informed of this, he suggested that this may be the problem and that it must have a 5-20 non-synth according to his techs. While some of this may be plausable, later in the conversation he said a few things that raised a red flag for me and I thought I would get your take:
Service Manager: "Yeah the tech smelled your exhaust and noticed it was sweet, that's how he knew you were running synth."

Two things about this struck me as odd.
1. Sweet = antifreeze (not oil) = terminal failure (I only notice a normal rich fuel smell on start up, nothing else, no white smoke, no blue smoke.)
2. My trunk was opened and I just happen to keep my oil and rags in a clear container there-maybe he smelled around my trunk

Service Manager: "Yeah he could smell it because it was getting past your seals."

I did not reply and just went along, but I have a DVD from Mazda on the RX8 that states that synth oil IS compatable with the seals, however no long term testing has been conducted. Moreover, if oil is getting through then where is the urgency to rectify the situation?

I had this car last winter and did not experience this. I will try to switch it to a 5-20 castrol again, but I doubt that Racing Beat, Rotary Performance, and others on this forum would be wrong in reccomending synth oil. How many of you agree or disagree with the service tech? Just looking for some advice here. (I have cleaned the MAF also-no change, but my air filter did have oil on it though.) Thanks in advance!

Jedi54

iTrader: (7)

Here's what I think of your service manager / tech.

YT1300

Exhaust sniffing techs, hm? Oh well, there's no accounting for some people's tastes.

I don't think a simple whiff test can pick up synth vs. non-synth oil; the sweetness of antifreeze comes from ethylene glycol, a toxic alcohol, so I can't imagine what that would be doing in non-synth oil.

Macius8

iTrader: (3)

The problem with the vibration may be a bad motor mount. There were some cases in which people had vibration and the mount was the problem. I currently have a similar problem and plan to check it out before turkey.

https://www.rx8club.com/showthread.p...on+motor+mount

max5roadster

Thanks Macius8! Wouldn't you know my car has 22,000+ miles on her-right within the 18k-25k group that noticed it as well! This is a vibration that makes my drivers side window rattle at idle. I will schedule another appointment and bring this up-shame their is no TSB, though.

Damien019

I actually just took my 8 in for this issue. I hit 19K about a week ago and complained of rough idle. Took it in, they said it was 2 of the motor mounts, didn't say which ones and I'm going back on Mon to have them replaced because they had to order them.

khtm

Yeah a lot of RX-8s had rough idle...I had it and I always used non-synthetic oil.

There's a bunch of threads that have people's theories on why the rotary engine is more prone to rough idle....try a search.

Also it could be the motor mount as Mac suggested.

max5roadster

khtm,
This is not the normal rotary exhaust burble/shudder that oscillates every such and such time. Having experience with a 87GXL and TII, I feel comfortable in knowing normal idle variations. This seems above normal. The entire car shudders-almost drones along with the vibration. I don't like to go into dealerships and let them know how much I know about automobiles because I am curious to see how they try to explain away problems when they think they are talking to a moron. I must admit, I was leaning more toward a plug replacement and had not considered a motor mount At 22k, it just did not seem very likely, but the above thread was very helpful. Searched "idle", got lots of nothing-the above thread admittedly was in the mix, but again, @ 22k, it just did not seem plausable, so I read some others-mostly flash related. :0

Damien019

I also thought it was a plug issue, knowing that some other people had some problems similar to mine. My service manager lives down the street from me though and knows that I know about cars as he sees me working on mine and my buddies cars often, good thing he's kinda friends with me so I expressed my concern about the plugs and he had me drive around with a tech. the tech agreed with me that it may be a plug issue and they called me later and told me that the motor mounds didn't look right, they weren't cracked or anything but needed to be replaced.

When I was self diagnosing this problem I noticed that sometimes the idle dropped, but it didn't always drop. At first I figured that this ma be because the tach lags a bit and sometimes the shutters were too quick to register. But we'll see when I get the new motor mounts.

KYLiquid

gasp! there might be oil in your exhaust system and muffler....WHOA...maby its all the oil the car pumps into the combustion chamber as part of its design......those techs sound like real tools....go somewhere else.

Nubo

"Wow, something smells sweet"

MadDog

They have been doing WAY too much exhaust sniffing. Now they are brain damaged.

beachdog

And yet the techs can't smell the gasoline in my oil...