Where is my oil disappearing to?

if they were an experienced professional, they'd know that a broken top ring makes the most difference to compression [and little difference to oil consumption], the second ring, much less to compression [and a reasonable difference to oil consumption], and the oil control rings, none at all to compression, [but a whole ship-load to oil consumption]. since oil loss is the the problem, and lack of compression apparently not, what conclusions do you draw here about the efficacy of a compression test here jason? hint: the professional mechanics' actions here should give you a clue.

dude, compression can vary quite a lot from cylinder to cylinder, and the engine still be perfectly serviceable with little oil consumption. i respectfully suggest you either get some training and experience under your belt OR you stick to topics you actually /do/ know about. thanks.

Uh, all ring sets contribute to compression AND oil control.

As an example, a couple of years ago I inherited an early 1980's Mazda B2000 P/U with about 160K miles on the odometer that was running lousy along with oil control problems. The reason, three pistons had broken compression rings.

In real life, cause and effect can vary widely vs. the published word...

JT

uh, re-read my post. the extent of compression and oil consumpton effect varies by ring.

Uh, you clearly stated that a compression ring makes little difference as relates to oil control. In fact, any broken compression ring will substantially affect oil control.

Additionally, broken oil or 2nd compression rings are rare since the malady is often caused by incorrect timing (or some other direct factor) that leads to detonation which is the chief culprit as to ring breakage.

JT

there are 3 rings: top and middle compression, bottom oil control. re-read what i said.

out of the 3, the top ring has the least effect!

yes, it's usually true that the top ring goes, but it's not always the case. and yes, it can increase oil consumption, but it's not as bad as the other rings. re-read what i said.

That agrees fairly well with my limited experience. I rebuilt an engine in a

Mike

Back in the early 1980's, I bought a friend's 1976 Honda Civic CVCC and drove it for about a year. It pinged fairly loud on hills and hard acceleration but luck was with me as I finally adjusted the timing to get rid of the knock. The car ran flawlessly all the way to the 170K (miles) mark when the car rotted out from under me...

JT

(Who wonders what adventures may lurk with his "new to me" '83 Civic FE)

recurred. Honda

obviously their

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Jim, I have a question for you. I was taught that the best method of detecting ring problems was to conduct a compression check. Other than taking the engine apart, are there now better methods of detecting ring problems? If so, what are so methods? Jason

You could do a wet vs. dry compression test as well as a leak down test.

Eric

for general engine health, i.e. how well it's coping with accumulated mileage, that's true. but in the situation cited originally in this thread, it's not guaranteed to diagnose the problem because defective oil control rings make almost no difference to compression. you're therefore left with logical deduction - if all other causes have been eliminated, it's the rings.

oil/excess deposits on one spark plug is a dead giveaway. in addition, oil analysis could do it, if conducted regularly. but in a situation where the engine's suddenly dry, analysis is not an option. that unfortunately leaves you with strip-down. but even then, there's not too much point messing about worrying what went wrong - once stripped, a motor needs to be rebuilt anyway and all the wearing parts need to be replaced, so just toss the pistons and rings and start again.

Eric, Thanks for your post. I have read about the leak down test but have never done one. Jason

Jim, Thanks for the information. I learned some things that I did not know. The oil analysis appears to be an excellent option. Jason

I checked the oil again Saturday and had to add another quart to bring it to full. I took note of the mileage and will be ready with a hard number of miles driven when I add the next quart.

I think the advice here has been valuable and suspect the rings problem now due to the input given. I'll let you all know how this turns out.

Thanks! Be

Yup - that's what it is sounding like. Best of luck to you.

Mike

I checked the oil again Saturday and had to add another quart to bring it to full. I took note of the mileage and will be ready with a hard number of miles driven when I add the next quart.

I think the advice here has been valuable and suspect the rings problem now due to the input given. I'll let you all know how this turns out.

Thanks! Be

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OK - here is what I found. I filled the oil to full and took an odometer reading. Some three weeks [667 miles] later, I needed to add 3/4 of a quart to bring it back to full again. You could extrapolate that out to say that for every 900 miles a quart is being consumed.

Be

That's a problem. File a warranty claim.

Took it to the Honda dealer today. The service rep claims that what I am experiencing is 'normal' oil consumption. He cites some technical bulletin written in 1988 that gives validity to the notion that a quart of oil lost every 1000 miles is normal. I just spoke to Honda at their toll-free customer service number and they are also claiming that this is their spec. They are not willing to open the engine unless I foot the bill.

What to do now? My inclination is to let an authorized Honda service center do an oil change and not add any oil for the next 3500 miles, letting the engine burn up. I only hope that it doesn't choose to fail when I'm in it with the family on a tall highway bridge. My warranty doesn't obligate me to top it off between oil changes.

Be

My warranty doesn't obligate me to top it off between oil changes.

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Hmmmmmmm. Careful . . . . Even lawyers can read the Owner's Manual.

'Curly'

That's funny. My '88 Civic with 244,800 miles on it uses less than 0.25 quarts in 3000 miles. Moreover, a service bulletin written in 1988 is not going to be applicable to a newer car. How could they have known what problems a 2005 model, for example, was going to have in 1988?!?!?

You may need to get someone to be your advocate and deal with Honda. I would take your car to a well respected independent Honda shop in your area and have them change the oil and then document the consumption (and absence of leaks). Then have them deal with Honda for you if they are willing, e.g., you've been or will be a good customer of that particular shop. Moreover, sometimes it's best to skip the dealer and go direct to Honda's customer relations.