Burning Oil

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1993 Civic DX, 197k miles. Purchased in July 2008, with me as second owner. In March 2009 it started burning/losing oil at about a half- quart per 600 miles.
-- Several times over the last couple of months I have thoroughly inspected the areas of the usual seals: dizzy o-ring, front crank and cam seals, valve cover gasket, upper and lower spark plug tube gaskets, oil pan gasket, rear engine seal. No leaks in these places that I can see.
-- Replaced PCV valve a month ago. No change.
-- Coolant level is steady; no signs of a head gasket breach.
-- Runs superbly, otherwise. 42 mpg averaged over 24 tanks of gas since March. I wonder whether the oil burning has upped the MPG a bit.
-- Inspected the spark plugs. They do not have black oil residue on them but all four are an odd, textured color of brown and not the usual properly combusting spark plug color.
-- Replaced valve stem seals a week ago. Still consuming oil. Thought it might be the valve stem seals especially because driving down a mountain using much engine braking yielded a report from buddies that smoke was blowing out of my exhaust. One buddy said it seemed blu-ish. Others were not sure.
-- Yesterday discovered the o-ring on the breather chamber had permatex ultra-gray or similar on it, apparently as a temporary fix. Also found oil residue beneath the hose connection to the breather chamber. I cleaned the chamber up and replaced the o-ring. I Hondabonded (I know, cheap) the grommet where the PCV valve hose connects to the breather chamber.
Questions: 1. When an oil ring or the valve guides fails, is it usual for all of them to fail at about the same time, thus explaining why the spark plugs are all the same color? This does not pass my common sense test, but maybe experience is a better substitute for common sense..
2. My theory with the breather chamber is that it was running at atmospheric pressure or so, and this may be higher than the usual pressure, meaning the PCV valve was open more often and wider yada than it should be. Comments?
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Elle wrote:

what brand of oil are you using? and what brand of gasoline?
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At purchase in July 2008, the dealer said Mobil 1 synthetic was in it. After noticing the high rate of oil consumption, I switched to conventional Pennzoil 5w30 oil. No change in oil consumption. I returned to Mobil 1 synthetic 5w30 in mid-August. No change.
I have been using regular unleaded Conoco Phillips gasoline, ethanol blended in where I live.
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Elle wrote:

well, plug deposits, barring a weak spark which you don't seem to have at 40+mpg, and poor gasoline, which in my opinion is debatable [!], is oil consumption. that leaves sudden onset of excessive wear [unlikely], all fours rings suddenly cracking [even more unlikely], or some kind of breather issue.
as you've found, stem seals are seldom much of an issue on your kind of honda because the seats are above the oil pool, so they only see a little splash, they are not submerged.
i'd go back over the breather system with a fine tooth comb. buy the right gaskets and replace them all, and maybe hoses too. i've seen silicone gasket flakes get all kinds of places and really foul things up, so make sure you don't have any floating about.
also, do a common-sense blow-by test on the motor. with the engine at working temp, carefully unscrew the oil filler cap. if the engine's breathing right, and you don't have a compression/wear problem, you'll get a bit of chuff out of the hole, [and some oil spray]. if there's something [badly] wrong, either the cap will want to shoot out of your hand as you get close to removal, or you can feel some vacuum if you have your hand over the hole. what you /should/ feel is a reasonable degree of positive pressure.
oh, and please confirm - this sudden increase in consumption - was it after first oil change after you bought the car? or later than that?
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It was before the first oil change that I performed. Here is the chronology:
July 2008 -- bought car. Dealer stated that it had recently had an oil change and that Mobil 1 synthetic was used.
August thru December 2008 -- I am sure I checked the oil level at least once, and it was fine.
Late March 2009 -- low oil warning light was going on when I went around curves. Had put 5k miles on car since purchase. Checked oil level. Was way low. Replaced oil and filter. Used conventional Pennzoil 5w30.
March thru June 2009 -- had to add about 1/3-1/2 quart of oil about every 600 miles to keep oil in spec. Regularly went near the low mark, and I would re-fill to 3/4 or so.
June 2009 -- replaced oil and filter, still using the conventional Pennzoil.
August 2009 -- thinking that the oil switch was the problem, replaced the oil and filter again, this time using Mobil 1 synthetic.
August-present 2009 -- still consuming 1/3-1/2 quart every 600 miles.
Tomorrow I will try the "common sense blow by test" you suggest. I will then also give the breather system more attention.
Tegger, I adjusted the valves on March 12 as part of routine maintenance and again last week as part of the valve stem seal replacement job (rocker arm assembly must come off). I have done several valve adjusts on Honda Civics now and doubt I messed this up. Then again, I do not have any other explanations for the sudden increase in oil consumption, and the March 12 valve adjustment does coincide with about when oil consumption first seems to have become excessive. The adjustments were done after the car sat overnight, completely cold engine.
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Elle wrote:

ok, do the breather stuff, then report back.
here's something to consider - an old "trick of the trade" is to use some of that crappy "stop oil consumption" additive when a dealer sells a known dud car. it works fine for a while, then, once a few months have gone by and it's no longer a quick come-back, it breaks down and oil consumption rises again. if consumption has been consistently high with subsequent oil changes, and you can't chase down a problem with the breather [remove the pcv valve and look inside the manifold for gunk evidencing excess flow], then my money is on this being an abused motor that's just worn. if that's the case, you're looking at living with the consumption or coughing up for a replacement motor, depending on your tolerance level.
does the cam appear worn? any grooves indicating lack of lube at some point in the past?
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I was not aware that such additives existed but I can certainly believe this is what happened and I got sold a car with a way worn engine. This may be a lesson of used car buying, even with a clean title and second owner status. Worst case I guess I may live with the oil consumption and then at some point chase down an engine to swap in.
I will keep this thread updated.
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Elle wrote:

avoid woolmort.

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Elle wrote:

There are two types of additives to lower oil consumption. One swells the valve seals; if you did the seal replacement right then you can rule that out. The other kind thickens the oil to slow blow-by past the rings. That would have been removed not long after the oil change. You can do a simple test to see if it's worn rings: pull all the plugs and the air filter, then run a compression test with the throttle wide open. If you have worn rings OR valves, the compression will be low. Then squirt about a tablespoon of higher-weight oil like SAE 80 or 90 into each cylinder and repeat the test. If the compression shoots up, you have worn rings. It if only rises slightly or not at all it's worn valves.
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Leftie wrote:

valves don't affect oil consumption.
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jim beam wrote:

Valve seals do, however. I was assuming that worn valves would be leaky as well, but maybe not.
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On 09/13/2009 03:39 AM, Leftie wrote:

read the thread - they've been replaced already.
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jim beam wrote:

Read my reply again: "One swells the valve seals; if you did the seal replacement right then you can rule that out." Ah, usenet...
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On 09/13/2009 04:34 PM, Leftie wrote:

why raise it at all if the o.p. had already ruled it out? [rhetorical] read the thread!
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I think what Jim Beam indicated is most likely closer to the truth. Here in Michigan one can buy a product called "CD-2 Helps Stop Oil Burning" - available in any supermarket for $3 or so. You put a bottle of that (if I recall, about 6 oz) with the oil change, and any oil burning stops ..... until the next oil change. Dishonest folks who want to dump/sell an old car with a worn engine will use this product, and the prospective buyer will never know it unless one is really careful about examining the car. Happened to me many years ago when I bought my first car as an unsuspecting (and naive) student (a used 83 Civic 1300SE). The car ran fine until the first oil change ... then, the same symptoms.... After learning from a sympathetic "Pro" as to what could have happened, I had to start using this CD-2 stuff with every oil change, and the car ran fine for about 40,000 miles until the blow-by became too much to handle (and one piston blew anyway). I was using 10W-30 dyno oil (Quaker State) with CD-2 and the CD-2 did its job almost to the very end.....
If this may be the case, you can try some of this additive and see what happens ... you may be able to get a bunch of miles out of the car as I did......
Good luck!

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It was before the first oil change that I performed. Here is the chronology:
July 2008 -- bought car. Dealer stated that it had recently had an oil change and that Mobil 1 synthetic was used.
August thru December 2008 -- I am sure I checked the oil level at least once, and it was fine.
Late March 2009 -- low oil warning light was going on when I went around curves. Had put 5k miles on car since purchase. Checked oil level. Was way low. Replaced oil and filter. Used conventional Pennzoil 5w30.
March thru June 2009 -- had to add about 1/3-1/2 quart of oil about every 600 miles to keep oil in spec. Regularly went near the low mark, and I would re-fill to 3/4 or so.
June 2009 -- replaced oil and filter, still using the conventional Pennzoil.
August 2009 -- thinking that the oil switch was the problem, replaced the oil and filter again, this time using Mobil 1 synthetic.
August-present 2009 -- still consuming 1/3-1/2 quart every 600 miles.
Tomorrow I will try the "common sense blow by test" you suggest. I will then also give the breather system more attention.
Tegger, I adjusted the valves on March 12 as part of routine maintenance and again last week as part of the valve stem seal replacement job (rocker arm assembly must come off). I have done several valve adjusts on Honda Civics now and doubt I messed this up. Then again, I do not have any other explanations for the sudden increase in oil consumption, and the March 12 valve adjustment does coincide with about when oil consumption first seems to have become excessive. The adjustments were done after the car sat overnight, completely cold engine. One observation that may be relevant: I found all exhaust valve lashes set at about 0.012 inch before I re-set them to the spec of between 0.011 and 0.009 (leaning towards 0.011). I found five of the eight intake valves' lashes were also set high. I am going to ponder this and of course welcome comments.
Thanks Jim and Tegger for giving this some time.
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Did this test. No shooting of the cap at all, nor any vacuum. With my hand on the fill hole, there was a pulsing positive pressure--chuffing as you wrote--and oil spraying/slopping onto my hand.
I gather this is not conclusive but a crude test for seriously bad compression, right? I expect to get an inexpensive compression tester soon and see what this yields.
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On 09/13/2009 06:55 AM, Elle wrote:

as it should be.

right.
based on the above, i guess you're looking at either worn rings or the breather system. fingers crossed on the latter.
this is not something i've tested, just suppose, but the oil consumption in my d15 engine has dropped substantially compared to when i first got it and after i'd fixed the leaks. my choice of oil has meant that pretty much all of the gunk and deposits in the engine have dissolved compared to the state it /was/ in. if this extends to the oil control rings, which do tend to accumulate stuff like this, maybe they're free to seal better, and thus reduce consumption? if that's true, and it is oil rings, maybe you should stick with this engine for a while and see what happens as your use of mobil 1 cleans things up.
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I will continue examining the breathing system and possibly replacing parts on it. Otherwise I think the course of action above is appropriate. Tegger has also written in the past about carbon accumulations causing malfunctioning oil control rings, causing increased consumption for awhile, then over time the carbon blows or burns off, and things return to more like normal.
I am not rushing to do a compression test right away because, as you noted Jim, and is noted elsewhere on the web, if the compression rings are not worn, but the oil rings are, the compression will be fine and so the test tells one nothing. Getting 42 mpg for the last six months suggests to me compression is likely (though not definitely) good. The tool is cheap enough and the process simple enough that I will do this sometime for my own education, though.
Thanks for sharing your experience Jim, Leftie, Priyantha, and Tegger. I will update if anything new arises.
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New info: I removed all the spark plugs again today and see I missed an important difference among them: Three of the plugs' ceramic areas (firing end, directly adjacent to where the spark occurs, not the wire end) are dark and look a bit oil fouled. One looks white-ish, the way it is supposed to according to photos on the web that discuss spark plug inspection. Considering the good fuel mileage, I am now leaning towards the problem not being the breather system but instead oil control rings on three of the pistons and Jim's and Priyantha's theory.
I cannot get a good photo of my plugs with my inexpensive camera.
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