Lurker here, finally became a member so I could post. As my sig (should) say, I have a 2000 accord LX 4 cylinder sedan with manual trans. I has just over 160k miles. Bought it with 54k. It has been excellent. About a year ago I had some issues and ended up replacing egr valve, distributor (plus wires & plugs) and eventually the cat (that one hurt). All the issues went away and the car runs great, except for oil consumption (I've heard this is a common issue with hondas). Burns about 1 qt per 500 miles - possibly even more (haven't totally finished testing this yet). It seems to burn more on the highway at higher rpms. So I decided to do a compression test. I just need a little help interpreting the results. I did a dry and a wet test and I recorded 2 numbers - the reading after 1 compression stroke and after 6. Here are the results:

Dry (first number is after one stroke, second is after 6.)
1. 105, 180
2. 110, 180
3. 110, 180
4. 110, 180

Wet (same 2 numbers)
1. 130, 200
2. 120, 195
3. 125, 200
4. 120, 200

Now all the cylinders seem to be close which is good. I've heard that compression should quickly increase but couldn't really find out how much? Is roughly 110 for the first stroke then up to roughly 180 a "quick" enough jump.

Second, I've heard that if you do a wet test and compression goes up it is bad rings. I've heard if it goes up 40psi that is bad but up 5psi is just fine. Mine went up about smack dab in the middle - roughly 20 psi. I guess I want opinions on whether that is bad or not.

Finally, I live where it is cold in the winter. When I start the car in the morning, I get a decent amount of smoke coming out of the tailpipe (not billowing), but that usually only lasts a few seconds then goes away. I've never noticed any smoke while I drive after the car warms up either.

I looked at the plugs (about a year old) and the two furthest to the right showed signs of oil burning - chunky whitish deposits. The two to the left looked normal. I park on the street and the car sits tilted toward the sidewalk a decent amount - don't know if that causes the two plugs on the right to show more signs of oil burn or not, just trying to give as much info. as possible.

Car runs great, decent power and gas mileage (28 hwy - used to be 31+ when I first got it) . I'm just worried that this oil consumption will ruin my new cat (and I paid a pretty penny for it). I guess I'd just like some help interpreting the results of my compression test and what to do about the oil consumption. Thanks for any tips or advice.

Also, just to add, I replaced the pcv valve. It hasn't changed the oil consumption. The vent tube that goes to the intake has some oil residue on it but the tube itself is clear of heavy deposits.
Also, I am fairly certain it is not leaking. It may leak a little, but no oil spots under the car and I degreased the engine and looked for leaks and couldn't really find anything. Also, I replaced the valve cover gasket about 2 years ago (oil had been seeping out). The inside looked pretty clean - no sludge or anything - just a sort of golden brown color on all the valves, cam etc. No more seepage out of the valve cover either.

 

my 4 cyl '92 5spd goes thru 1 oil qt/ 1800 miles. >220,000 miles

Your compression figures look good to me.
Have no info on cat being harmed by oil consumption;
seems plausible, but no independent evidence from here.

Info only it seems, luck.

 

From experience, compression test results have little correlation with oil consumption i.e., the compression rings can be in excellent condition while the oil control rings can be coked-up resulting in a great running engine with high oil consumption. That said, I would rule out valve guide seals before replacing the engine since you're seeing smoke at start-up. Replace them to see if the oil consumption goes down.

My F23A1 (similar to your engine) consumes about 1qt/6000 miles.

 

I asked my mechanic about my oil consumption and that is what he said was likely the problem. The oil control rings and not the actual compression rings.

Is there any way to fix this short of a rebuild with new rings? I think I read somewhere about pulling the plugs and putting something in the cylinder to break the control rings loose or revitalize them in some way. Anyone ever done this?

Like you said Roader, the smoke at startup makes me think valve seals, but can that much oil be consumed through bad valve seals?

Thanks for the quick replies guys. Keep em comin!

 

Those compressions look good to me.

Check for smoke from fully warmed engine after a prolonged idle and acceleration. This and smoke on startup are symptomatic of worn valve stem seals.

Have you checked carefully for oil leaks?

PCV system. Inspect throttle plate for evidence of fresh oil. If oil on throttle plate and duct, then oil is being pulled into duct through PCV air intake (reverse flow). This happens normally under heavy acceleration, but should not happen frequently. It is usually a symptom of excess crankcase pressure. Check PCV system carefully (PCV valve and hoses) and observe manifold vacuum level for evidence of low vacuum levels and postive crankcase pressurre.

If this car has had regular maintenance, I would look very hard for oil loss diagnosis before a rebuild.

good luck

 

What I noticed with the oil-burning engine was that the engine oil would get real dirty, real fast. It would be almost black 1K miles after an oil & filter change. The current, non-oil-burning engine's oil is still a medium amber color after 6000 miles. I think the dirty oil indicates combustion byproducts getting blown past bad oil control rings. I don't think I'd have seen the oil getting dirty if valves seals were the culprit. Bad valve seals would just allow clean oil to get sucked into the combustion chamber.

I did try soaking the pistons on the old engine: MMO Soak Halved Oil Consumption. Even so, 1qt/800 miles was too much oil so I got a new (used) engine.

 

There doesn't appear to be anything wrong with your engine based on those numbers. It would appear more towards external leaks.

 

The dirty oil is happening with me too. It's almost like I change my oil, drive a few hundred miles and it already looks black. My other cars hold a golden brown color almost until the next oil change. I only get a little burn on startup (and that's not even every time - usually only right after a change or on really cold days) and never after the engine is warm so I'm thinking the valve seals are probably not the culprit.

Given that it looks like probably oil control rings, I'll try the piston soak and see if that helps at all. I was considering increasing my oil weight too. I run 5w-30 but was considering 10w-30 or even 10w-40 to see if that helps. Anyone have any experience with that?

Thanks for all the replies. I was on vacation for 10 days so that's why my response was delayed.

 

Keep in mind that 10W-30 is no "heavier" than 5W-30 (or even 0W-30 for that matter); if you really want a heavier oil, use 0W-40, 5W-40, or 10W-40. That said, I've been wrenching on cars for over 45 years and I've never once seen a higher grade oil do anything positive regarding oil consumption.

 

X2. A switch to 10w40 did nothing to reduce oil consumption. Elevation changes increased oil consumption. Around town, all flat driving, would get 600 or 700 miles/quart. Denver to 1-15 via I-70, it would be a a quart down by the time I got to Green River.

Fragile automatic transmissions in 6th Gen cars creates a good supply of low mileage used engines.