Oil consumption, fouling in cylinders 3 & 4...rings?

[novaraz]

I have a 2008 Speed3 GT, bought new (135,000 miles now). By far the most favorite car my wife and I have ever owned. It's pretty much stock, except for Bilstein struts and shocks, and 2010 wheels.

About 6 months, several symptoms started occurring:
-Oil consumption of about 1 qt/1000 mi
-Noisy chatter on start, disappears after 1 second
-Occasional hard starts with warm engine
-Occasional misfire MIL

Otherwise, the car runs great. No noticeable loss of power, acceleration, etc.

At the safety inspection, the shop removed the intercooler, and found no pooled oil, very little play in turbo shaft. Plugs in cylinders 3 and 4 were oil fouled (all 4 plugs were changed about 30k miles ago). The mechanic thinks its failing piston rings and recommended using 5W-40 for now. I trust him, but I would love the community's very knowledgeable (which I have lurked for many years daydreaming about upgrades) input. Any chance this could be a valve problem?

[tom10122]

Noisy chatter is most likely the timing chain tensioner. Open the oil fill cap and you can check it. It should be taunt if it was just running or running recently.

Do you have a boost gauge? How much vaccum does it pull at idle? It should be 20inHg. I had a vacuum leak and it would have a random misfire at idle and be hard to start when warm. If you have a Cobb AP you can up the idle and see if that helps, it did for me but eventually it went away by itself in my case.

I'm curious about your oil consumption myself. I'm going through a quart every 250 miles but no problems other than that (no fouled plugs or misfires)

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[aackthpt]

Originally Posted by tom10122 I'm going through a quart every 250 miles but no problems other than that (no fouled plugs or misfires)

Yeah but at that rate you have got to be part of Club Blue Smoke Screen.

[tom10122]

Originally Posted by aackthpt Yeah but at that rate you have got to be part of Club Blue Smoke Screen.

None at all. I have both cats though.

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[mazda62006]

Well, I have to tell you, I don't think the cats mask the smoke at least not the amount you think. I have has the same problem with no noticeable smoke and running a downpipe. I would do a compression test and check for leaks. If you are running fine and the power is good, I would suspect oil control rings.
I agree with the other poster on the chatter, could be the chain. Check it, if it is the problem have it fixed

[Cdnspeed6]

compression and leak down test if those are good, I'd suspect the Turbo is starting to Blow through oil

chatter in the morning is most likely VVT hop on it before it cause more damage

[novaraz]

Thanks for the replies. I will double chain the chain; I poked it once and it was tight, but I don't remember if the engine was warm or cold.

I will plan to do the compression and leak down tests. Hopefully the rings pass the test. It could still be a turbo, even if minimal oil was found and little/no shaft play?

[novaraz]

To fix the VVT, you need to completely disassemble timing chain? Looks like a big job, right?

[tom10122]

Originally Posted by novaraz To fix the VVT, you need to completely disassemble timing chain? Looks like a big job, right?

Yes, I was quoted $950 by my dealer

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[deuce_WI]

A shot PCV will cause oil consumption too. It's cheap but in a pain in the ass location on these cars. Some say you can swap it from below, but I pulled the IM to do mine.

When I'd park the car in the garage after a good hard drive and then come back to it 30 minutes later there would be a faint hot oil smell in the garage.

[LowFlyin]

Originally Posted by novaraz To fix the VVT, you need to completely disassemble timing chain? Looks like a big job, right?

Yes and yes, along with proprietary tools for timing.

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[novaraz]

I checked the chain today while warm, there was a bit of slack, maybe 1/4 inch. No where near as bad as this guy: https://www.youtube.com/watch?v=ZQI8SHKPEXI

Regarding the oil consumption, I am switching to 5W-40 and will monitor the consumption.

[tom10122]

There should be none when warm

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[novaraz]

Originally Posted by tom10122 There should be none when warm Sent from my XT1565 using Tapatalk

Do you think it's an urgent repair with just a bit of slack? My funds for repairs are low, I was hoping to get another 10k miles before more $. Plus the shop didn't mention anything yesterday.

[tom10122]

I'd do it sooner rather than later, take it easy, no hard downshifts.

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[novaraz]

If I crank the engine without starting (by holding down the gas petal), "prime" oil pressure for ~5 seconds, the car starts without any rattle. Is this just treating the symptom, or is it an anti-drainback oil filter issue, a la this thread?