Burning Oil

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Then there's your culprit: Worn rings.
Because modern oil combusts very cleanly, it takes quite a high level of consumption to cause deposits on the plugs.
Are the deposits sooty with a bit of an oily feel to them, or are they actually covered in liquid oil?
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Tegger

The Unofficial Honda/Acura FAQ
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They are much closer to sooty with an oily feel than they are to looking liquidy. E.g. they are nowhere near as liquidy and bad as the "oil fouled" plug shown at http://www.cyclefish.com/forum/topic/15/index/3706/1#3821 . Do you think this matters?
Like I wrote, the ceramic part just beneath where the spark occurs is black-ish, sooty-ish on three of four of my Civic's plugs. Where the spark occurs is a textured brown, like some deposits are accumulating there, but they're not black (yet?). I figure this is because 1/2 quart every 600 miles or so is not a lot of oil burning. A concern, but it could be a lot worse.
I should have wrote my theory now is that it is either the oil control rings /or/ the valve guides that are going. I have looked into replacing the valve guides but assuming I wanted to gamble that it is the guides and not the oil control rings, it seems cheaper to just buy a new head. I think I'd consider a new used engine from a reputable used Honda engine seller, first.
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Elle wrote:

The compression test with and without heavy oil may help you to decide. It takes 5 minutes.
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Leftie ( snipped-for-privacy@Thanks.net) writes:

Since you have resigned yourself to possibly replacing the motor in the distant future, try experimenting with heavier oils (20W50, 20W40, 10W40). Looks like you have nothing to lose. 1200 miles per quart isn't great, but its not that bad. At least it isn't 500 miles per quart. Try a 20W50 oil for 2000 miles and see if the oil consumption is reduced. Try what the other person said, which was a 10W30 oil and the additive called "CD-2".
I wonder if that stinkin' dealer just dumped in the cheapest 20W50 or straight 40 weight oil he could buy, and told you it was Mobil synthetic.
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snipped-for-privacy@FreeNet.Carleton.CA (M.A. Stewart) wrote:

Yes I think this is definitely worth experimenting with a little. I will probably give the Mobil 1 a chance for another six months, then try a heavier oil.

I will research the CD-2, thanks.

Yes it is something to wonder about. It was a new car (Nissan) dealer who of course flips trade-ins. They explained they rarely took such old cars and sold them off the lot. It could have been the original owner who possibly added something. Either way, ISTM when a car has more than say 150k miles, it is all about buyer beware, no? Even with a 1-owner car. Maybe this is why new car dealers rarely deal (as far as used car sales on the lot) with cars more than ten years old, except to auction them elsewhere.
Fortunately, very worst case, if this car should suddenly die on me, no big deal. I will go chase down another used car, this time more carefully researched. Though I think it is unlikely it will die; it really does run well, and I am on top of its maintenance. Meanwhile I will run some "experiments" as we are calling them at this point and try to learn more.
Thanks for the input.
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On 09/14/2009 07:30 PM, Elle wrote:

stay away from that stuff. it cokes up engines something chronic. it's just a short term fix designed to shift junk off a sellers driveway.

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I agree. Just use the highest viscosity the manual recommends for your temp range and keep a few bottles in the trunk. Just keep checking it once a week and add as needed. I actually think 1200 miles per qt is fine for a car with 190,000 miles. If it doesn't make it to a quarter million, it won't be because of this oil burning problem (unless you run it dry).
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On 09/15/2009 06:02 PM, Gordon McGrew wrote:

mine was burning at that rate, but has since dropped to one quart per 4 or 5k.
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On 09/14/2009 04:04 PM, Leftie wrote:

that tests compression rings, not oil control rings.
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On 09/14/2009 11:32 AM, Elle wrote:

it's /not/ the valves. you've just replaced the seals. even if the valve guides are chronically worn, if the seals are sealing, there's no oil loss.
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A lot of auto maintenance sites (not just random people posting) state that either the valve stem seals or the valve guides may be failing. I understand what you're saying but it is hard for me to say from the Civic shop manual drawing whether a new, properly installed valve stem seal alone will ensure no leakage in this area.
Regardless, for now I am going the route of trying to clean things up with continued use of Mobil 1 and/or maybe Auto-RX.
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On 09/15/2009 03:53 AM, Elle wrote:

1. your honda valve guides are not submerged. 2. it's been known for internet "experts" to be full of it. 3. i've experimented with /no/ seals - you lose a little, but it's not a massive source of loss.

unless it's lost flexibility, is worn or cracked, it will.

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wrote:

It doesn't matter. Oil is being flung all over the inside of the valve cover. If your guides are worn and your seals are worn, oil will be sucked in through the intake guides.

True
True as well. I've had engines that did not even use valve stem seals (Jensen-Healey 2.0L Lotus 4 cylinder) and others that only used them on the intake valves. However, when you say "you use a little," that might add up to a lot in the eyes of some people. For a new engine with minimal valve stem to valve guide clearance, the loss will be small. However, for an older engine with worn stems and guides, the loss can be significant. In the old days this was still trivial in many cases. However, with modern engines, severely worn guides can casue several problems - excessive air leakage will screw up the PCM's calculation for fuel delivery and excessive oil consumption can damage a catalytic converter.

New seals will help, but becasue of the excessive play, they won't last as long, and they will still let more oil past than seals on unworn guides and stems. Seals have to allow some oil past to keep the valve stems and guides lubricated, so they aren't perfect seals by design.

If the engine is only using a half a quart per 600 miles, I'd just drive it. With 197,000 miles on the engine, it is not just the valve train that is worn.
Ed
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Thanks for the further input, Jim and Ed. I will try to get a better look at the valve guides on the next trip to the junkyard, for continued education on this point.
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On 09/15/2009 06:58 AM, C. E. White wrote:

it does matter - submerged guides can leak literally pints.

right, but that's a whole different issue.

but they are literally weeks old - no "lasting" problem.

untrue - the stems and guides run dry. the seal is there to do just that - seal.

a honda should be up there at at least 300k.
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Tegger wrote:

IMO, it's also possible that the rings are merely gunked up with carbon deposits. (Barring abuse, a 200K Civic should be far from worn out, right folks?) If so, it might be possible to clean the gunk and free the stuck rings, allowing them to resume normal service.
Does the engine have any sludge, or other signs of over-stressed oil?
I'm not a big fan of oil additives, but AutoRx seems to be a legitimate product that actually works. It's a mix of esters that are quite effective in cleaning up sludge and carbonized oil from your engine.
Or you might try running a good synthetic for a few changes. Pick one with a close spread of viscosities, ie. 10w-30. Such an oil should have fewer volatile viscosity index modifiers; these VII additives are supposedly one of the main sources of engine deposits. Over on BITOG, M1 10W-30 high mileage mix has a good reputation for cleaning, but any good 10w-30 Syn should help. If you really want to clean the car, run Redline. It's ester based, VII free, and cleans like mad.
One of these options may well help, and will be vastly less expensive and troublesome than disassembling the engine.
0.02c
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ps.
Here's a pretty good BITOG thread discussing coked-up rings. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number 60891
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I have not taken off the oil pan, but during the three oil changes since March, I did not notice sludge when transferring oil to an old milk jug for recycling. I was under the valve cover doing the valve stem seal replacement and of course mopped up a lot of oil in the process. It did not seem sludg-y or particularly dirty.
I read the Bob-is-the-oil-guy thread and am researching the AutoRX further, for one, now.
Thanks for the input.
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Have you exmained the spark plugs? Differences in coating color and deposition are tell-tales to engine problems.
If one plug is significantly different than the others, then you know there is an issue with that cylinder.
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Tegger

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On 09/14/2009 10:13 AM, Tegger wrote:

or it's the only one working right!
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