Just a quick back story - 120k-ish miles on original motor and car. Car apparently had a head gasket put in it before purchase, yadda yadda. Car purchased and it burned oil, approximately 1 quart every 1,000 something miles. Drove car for 2 years adding in oil every so often until we decided to fix it as it progressively seemed to worsen. After some time we checked it out.

Cylinder 3 had oil inside the spark plug tube but not from the tube seal leaking. Also, the plug threads and electrode had oil on them. Cylinder 4 also had the same symptoms but not as much oil. Other two cylinders had a slight bit of oil on the plugs also. Checked compression and had 160 PSI across all 4 cylinders evenly. Car ran perfectly with no problems but after a while started to develop blue smoke on take off. We then used a leak down tester to figure out where everything was going and found what appeared the be the valve stem seals leaking. I know this is a somewhat common issue in the D15B7 up around 100k miles and beyond. Also, the car was in need of maintainence.

Decided that if we were going to do the valve stem seals we would just install a completely rebuilt head and all new gaskets, plugs, wires, etc. Might as well freshen everything up while it was all apart. We swapped the intake and exhaust manifolds from the old head to the new one along with the sensors and everything else. The rebuilt head came all the internal stuff to the head, just none of the exterior things. We installed the head, set the timing, changed plugs, wires, cap, rotor, coolant, etc. to get it read. Fired it up and it started with no issue, perfect oil pressure, no smoke and ran great, no issues.

Started driving the car and noticed that it seemed to still be using oil, but no smoke. Coolant was at the same level with only a slight bit of dirt in the overflow, no issues there with the headgasket or anything not sealing properly. Checked the plugs and tubes. This time only cylinder 3 had oil on the spark plug and some in the tube. Once again, not from the tube seals. The other 3 were perfectly dry, no traces of oil at all on the electrode or in the tube.

Now my question is this - why only cylinder 3? How would oil get in the tube without the tube seal being bad? I would figure if the oil control ring was bad on 3 that it'd be bad on the other cylinders too. What else could cause oil to only burn on 1 cylinder?

 

Mostly as a double check: You have replaced (not inspected; installed new ones) both the upper and lower seals in spark plug tube 3, right? The upper being the gasket in the valve cover going around the spark plug tube, and the lower being a special shaped o-ring sealing between the rocker arm and head, per the top two drawings at http://honda.lioness.googlepages.com/oilleaks .

I am battling an oil consumption problem on my 93 Civic DX as well. Replacing the valve stem seals did not fix it.

 

I will check again to make sure that seal is there, but yea, for some reason it looks like cylinder 3 has a different seal than the other 3 cylinders. I will check into that next time I look at the car. I can't imagine that if the oil control ring were bad on cylinder 3 that oil could get up passed the spark plug and into the tube. I'd imagine that the lower seal has to be bad, especially since the upper portion of the tube is completely dry. Could be possible that the rebuilt head we got that maybe he forgot to put that seal in.

Any other ideas?

 

My cylinder 3 spark plugs had oil on it as well, I did valve seals and new rings and it's fine now. I did RTV the Oring on the rocker assembly, I think it was a different shape than the others?

 

Yea, from what I can tell from the pictures cylinder 3 has a different seal than the other 3 do. Going to take a look and see if I can see anything. Compression on the engine was great and the oil appears to be coming from up top. If the oil control ring was bad on cylinder 3 there's no way the oil would be getting up into the tube passed the threads. And like I said, the top of the tube is fine, just that the bottom had oil. Other 3 cylinders are perfectly clean.

 

To test the piston rings compare dry versus wet cylinder compressions. This is done by comparing compressions after addition of nothing to the cylinder or after addition of a tablespoon of oil.

Just curious, how do you know the oil on the outside of plug 3 is not coming from a leaking tube seal? Is there any oil on the cylinder side of this plug?

Are there any visible oil leaks from the engine?

 

Wet versus dry compression tests yield a ~20 PSI increase in compression. This is far within standards, seeing as how liquids do not compress and this would add much less area for the compression charge to squeeze into. Numbers are almost the exact same across all 4 cylinders, with maybe 2 PSI difference.

The oil is not coming from the upper tube seal. For one, the seals are brand new and were installed with the rebuilt head. Two, there's absolutely no oil near the tube seal inside the tube, only at the bottom and just a slight puddle. Other than that the tube is dry. There was some oil on the cylinder side of the plug. I can't imagine that it would be leaking passed the threads of the plug from the tube seal but I guess the vacuum of the engine could also be pulling it in. This is what I'm trying to figure out is if the oil is leaking down into the cylinder somehow.

No visible oil leaks from engine. Engine was completely degreased and cleaned prior to cylinder head installation. Oil is not entering cooling system either as cooling system is at exact same level after just completing cylinder head installation and has no sign of oil.

 

Based on what you are saying, the piston rings are similar for all four cylinders. Nonetheless, you are burning some oil in cylinder 3 but not the other cylinders. Could a bad cylinder 3 O-ring allow oil into the cylinder and thereby explain the oil burning? If not, I think cylinder leak down tests may be warranted.

 

You can try doing a valve lash adjustment and new valve stem seals. Those can make the engine smoke under load. Otherwise yank it and drop a different engine in. The B7 isn't bad, but it's not great either.

 

If you replaced the valve seals in the head and it's still burning oil, it's the oil control rings. In your case, cylinder 3 most likely has a bad oil control ring. Or a cracked ring land where the oil ring sits. I mean the upper compression rings on that particular cylinder are most likely fine giving good compression but the oil control ring isn't doing it's job.

How does the spark plug tip on cylinder 3 look like? White crusty residue deposits on the electrode with some black fouling on the insulator? How does the piston top look like when you shine a light down the spark plug tube? Does it look "wet" like oil is on the piston? Do the other 3 cylinder piston tops look "dry"?

 

Yes it is different (see photo below) but if replaced properly, it should be fine.



ISTM it would be easy enough for any of the four seals shown above to fall a little out of position during re-installation of the rocker arm assembly. I clean the old baked on oil in the areas of these seals out and then use engine oil to lube the new seals up. When I lift--briefly--and place the assembly onto the head, the seals always adhere fine. But I could see one or more falling out of position a bit. Or maybe the installer did forget this seal or used the old one, like you suggested? Or maybe some people just go to their local hardware store and buy o-rings that seem to fit for tubes 1, 2, and 4 but neglect tube 3 or jury rig it with liquid sealant? The temperatures can get pretty high in there so personally I am reluctant to trust any o-ring for the lower tube seals. Plus it is a busy half-day's work replacing them and I do not care to repeat the job. Hence I pay the bucks for the OEM ones.

Maybe for #3 spark plug tube beneath the lower seal and around the top of the spark plug: Stuff a bit of rag, then some aluminum foil as another layer, then as the final layer a bit more rag. Take a drive. Carefully inspect the rags afterwards, seeing if the bottom is oil soaked or the top is.

Replacing these lower seals is not too a hard job if you are an advanced beginner or so and can do the required valve adjustment afterwards. See the link I gave earlier.

I agree this seems unlikely.

 

I purchased my 93 Civic DX in July 2008. I do not think it was losing any significant oil for at least about the first six months. Then starting in about March 2009, my Civic started burning oil at a very noticeable rate. Like the OP's, it burns about a quart every 1000 miles. The oil is not leaking from anywhere; I cleaned the engine and have inspected it several times since March. The spark plug tubes are dry. I replaced the valve stem seals about ten days ago; no change in oil consumption. The plugs do not show black oily residue but all are a textured brown suggesting to me some oil burning. They do not look the way photos show proper combusting plugs should.

My Civic has been getting 42 mpg since March. I am careful in recording mpg at every fillup. I fill up with about 1-3 gallons left in the fuel tank. So it seems doubtful the compression rings are failing. The oil control rings are another matter, though. Yet I am not experienced enough to say, as the plugs seem to suggest, that all four oil control rings are failing at the same time. This seems improbable but I really do not know. I suppose the previous owner (only one; I am second) could have driven the engine hard, and so all four oil control rings are failing.

I do my own work and I have studied my maintenance records. One thing I noticed is that I did a valve adjustment on March 12. This was the first I had done on this Civic. I took notes on the settings prior to my loosening the adjusting nuts. All the exhaust valve lashes were set slightly high at 0.012 inch (spec is 0.009 to 0.011 inch). Five of the eight intake valve lashes were high out of spec (did not record numbers).

I set all valves to spec. I have done valve adjustments before and had not had any problem. I aim for being closer to the high spec, since I would rather deal with a little noise in the morning on cold start than risk a burnt valve by having the lash set too tight at less than or equal to the low spec.

About March 26, my oil warning light came on when going around curves or being on hills etc., and I was surprised to see how low the oil level had gotten.

Thumper or anyone, is there justification for setting the valve lash a bit higher on older Hondas to prevent oil burning? I am trying to figure out a theory as to why wider valve lashes would tend to burn less oil than smaller ones, especially on older cars.

 

It's hard to believe that ONLY cylinder 3 would have a bad oil control ring and the other cylinders are perfectly fine with no issues at all. Also, as stated, if the oil control ring was bad on that cylinder you would see a significant increase in compression on a wet test. As stated, the difference on all cylinders was 20 PSI in wet v.s. dry. If the oil control ring on cylinder 3 was bad I would assume that you'd see some different results instead of the same.

I can speculate that if the o-ring on 3 was bad or missing that it would cause the car to leak oil into the tube and burn it. If you guys haven't been reading, a rebuilt head was installed. It was complete with all new seals and o-rings and obviously I did the valve lash adjustment when I installed it. All the adjusters for the rocker arm were loose when it was sent, so adjustment was necessary. Also, I'm not sure if wrong valve lash adjustment would cause one to burn oil. My 94 Accord EX had bad valve lash adjustment (could hear the ticking bad) and it used half a quart of oil per oil change. Also, the girlfriend's 97 DX has had the valve lash adjusted on it and it burns almost no oil between oil changes.

Doing those o-rings would obviously not be a hard job for me to do, seeing as how I just installed the cylinder head and everything. lol I'm an automotive technician for a living and have done things like this before, just that I have had not much experience with diagnosing burning oil. If a car is burning oil it usually does not come into our dealership shop. lol Like I said though, I'm more than sure the old valve stem seals were bad. All cylinders showed signs of burning oil before, and now only one does after the head replacement. Also, the previous leakdown test showed the compression coming from the oil cap on the valve cover.

 

Could someone please explain to me how a bad O-ring for cylinder 3 would allow oil to be burned by the cylinder 3.

 

Try changing out your PCV valve or breather box on the block. Either one can be clogged causing excessive blow by since you mentioned pressure coming out the oil cap when you did the leakdown test.

I don't think adjusting the valve lash would prevent any kind of oil burning. Bad valve lash mostly results in misfires, or poor engine performance. I mean if your valve seals and all other head seals are brand new, and the oil is burning still, the only other factor is the oil control ring or a cracked/damaged ring land where the oil ring sits on the piston.

If the oil control ring is failing, oil would be in the combustion chamber and if you shine a light down the spark plug tube, it would look "wet" on top of the piston. And with the engine making compression while running, oil in the combustion chamber can seep up into the spark plug threads and travel up onto the base of the spark plug.

 

I would only figure a bad lower spark plug tube seal would let oil into the tube, not necessarily down and around the spark plug inyo the cylinder. Do you think it more likely that the oil in the tube is due to a bad oil ring on the #3 piston?

 

This was my thinking as well.

So if the rather significant oil loss cannot be explained by the O-ring leaking a small amount of oil into the spark plug tube, one must presume that the cylinders are burning oil and that most of this oil burning is occurring in cylinder 3. This oil burning could be due to bad piston rings, head gasket, or valve seals. Are there any other possibilities? The compression test results don't fit very well with bad rings or a bad head gasket, though a leak down test should be done to verify this idea. Isn't it possible that the new valve seal(s) for cylinder 3 is bad and leaking?

I just can't see how this could happen, unless the spark plug is loose or there's a problem with the spark plug threads or the corresponding threads in the head.

 

Note on something about which I am not sure at this point: Can the OP please clarify as to what the rate of oil loss currently is?

I am bearing in mind that a good compression test says the compression rings are good but says nothing about how the oil control rings are.

Yes, and I have read of people installing these wrong. So I would not eliminate this, though yes it remains puzzling how the oil is getting past the plug into the tube, unless some kind of double failure is happening here (bad lower tube seal and bad something else--oil control ring or valve stem seal?). A double failure seems improbable.

 

I inspected the 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 being the oil control rings or the valve guides, as in an old engine or one driven hard.

I understand it is possible that the oil control rings may have a carbon buildup that precludes proper operation, and running the engine with Mobil 1 synthetic (among other oils) will tend to clean up the carbon, so the oil consumption may diminish. So I will go this route a while.

The theory some other Honda people at another forum put forth on why this oil consumption problem took around eight months to appear: The original owners or the dealer used an additive that cuts down on oil burning, but the additive breaks down over time or, with an oil change, is no longer present.

 

Wait, what type of oil do you use? I stay away from Mobil 1 or any synthetic cause it tends to burn a lot in Hondas. I've read in some instances where Honda owners that ran synthetic switched to conventional and they didn't burn as much oil afterwards. Stick with a conventional oil like Castrol GTX and try using 10W-30 as compared to 5W-30 since it's a bit thicker on the cold side.

 

I switched from synthetic Mobil 1 to conventional Pennzoil 5W-30 in late March, and the oil burning continued, 1/2 quart per 500 miles or so. I switched back to Mobil 1 synthetic in early August. Still burning oil at the same rate.

I hear you about using specifically Castrol and a higher weight. I see many recommending this. It's worth a try. :-)

 

Bring this back up with some information.

I checked out this car again yesterday. All of the plugs besides cylinder 3 are perfectly tan with no signs of burning oil. Also, the tube seals on all besides cylinder 3 are perfectly dry. Cylinder 3 shows oil sitting at the bottom of the tube, not leaking down from the top. Also, the car shows no smoke at all when driving it under any conditions.

Oil consumption is currently around a quart every 800 miles or so. I wonder if it is possible that a valve stem seal was installed incorrectly or if the tube seal at the bottom is bad. I still can't imagine how only one oil control ring could be bad yet the others are perfectly fine and have no signs at all of burning oil. I am going to e-mail the seller of the rebuilt head and see what he has to say about this.

I'm going to have my brother-in-law switch to Castrol GTX 10W30 and see if it continues to burn oil at the same rate.

 

my cylinder 3 rings went a few months ago (150 psi compression), it was only that cylinder. oil on spark plug, didnt wait long enough to see how much oil i burned. rebuilt with new rings and its fine now. itll smoke if its valve seals i thought?

 

Screw it, pull the engine. I ripped my old D15B7 apart with 180k miles and the cylinder walls were smooth in areas.

 

The problem with putting new rings on is that I have to pull the head again. I'm really debating leaving the motor in the car and rebuilding it from there and just putting in new rings. IIRC, aren't you supposed to re-hone the block before you put new rings in? I know that I would just re-use the old bearings and such in the bottom end since they're all fine still. Is it possible to install new rings with the head still on or do the pistons always have to be put in from the top?