Burning Oil

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?

 

what brand of oil are you using? and what brand of gasoline?

 

what brand of oil are you using? and what brand of gasoline?

 

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.

 

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.

 

That's a quart every 1,200 miles. Not good at all for less than 200K
miles.

The idea that a plugged PCV valve by itself will increase oil
consumption is common but erroneous.

A good sign.

I suppose it's possible. The oxygen sensor would detect the excess
hydrocarbons from the oil and compensate by reducing injector pulse
width.

Modern motor oil is a readily and cleanly combustible hydrocarbon mix.

Can you supply a clear photo of the plugs?

Smoke on overrun indicates worn rings, not valve guide oil seals.

I think you need to have a compression test done. If the readings go up
for the wet test, the rings are very worn.

They won't necessarily fail all at once, but it only takes one cylinder
to fail for smoke to show out the tailpipe. Two things you can have in
that case: A slightly lumpy idle, and an odd-man-out compression test
reading on one cylinder.

I have a feeling you'll find that one cylinder has much lower
compression than the others.

If one cylinder is much lower than the others, there's a tiny
possibility that the rings are simply carboned up and not sealing as
they should. In that case, long-term use of Mobil 1 and some occasional
spirited driving may free it up.

By the way, when was the last time you checked the valve clearances?

 

That's a quart every 1,200 miles. Not good at all for less than 200K
miles.

The idea that a plugged PCV valve by itself will increase oil
consumption is common but erroneous.

A good sign.

I suppose it's possible. The oxygen sensor would detect the excess
hydrocarbons from the oil and compensate by reducing injector pulse
width.

Modern motor oil is a readily and cleanly combustible hydrocarbon mix.

Can you supply a clear photo of the plugs?

Smoke on overrun indicates worn rings, not valve guide oil seals.

I think you need to have a compression test done. If the readings go up
for the wet test, the rings are very worn.

They won't necessarily fail all at once, but it only takes one cylinder
to fail for smoke to show out the tailpipe. Two things you can have in
that case: A slightly lumpy idle, and an odd-man-out compression test
reading on one cylinder.

I have a feeling you'll find that one cylinder has much lower
compression than the others.

If one cylinder is much lower than the others, there's a tiny
possibility that the rings are simply carboned up and not sealing as
they should. In that case, long-term use of Mobil 1 and some occasional
spirited driving may free it up.

By the way, when was the last time you checked the valve clearances?

 

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?

 

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?

 

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.

 

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.

 

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.

 

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.

 

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?

 

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?

 

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.

 

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.

 

avoid woolmort.

 

avoid woolmort.

 

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.