Burning oil, cant find out where

[hankooks2k]

Last night i was driving and i gave it some gas and passed a car, i looked in my rearview mirror and i saw some smoke out of the exhaust. I couldnt tell what color it was because it was nighttime. I was worried it was oil, so this morning before work i checked my oil and i was at the first "x" above the L, so i was about a quart low. so that was a good quart burned in about 1 month. thats too much, i dont got hot rodding around either, so im kinda worried now.

i looked around the filter, drain plug, and the pan, no leaks. oil pressure light has never come on so no major leaks anywhere. if im burning oil, where are the possibilites? can a bad valve adjustment cause oil burning? im afraid that i could be burning oil through the cylinders through the piston rings or maybe the cylinders could be scored? im trying to think of all of the possibilties. any suggestions?

[desmo4]

How many miles are on your car?

Jonathan

[hankooks2k]

130k miles. recently just got the head machined and a valve job because they weren't sealing/seating correctly and i had a minor exhaust valve leak. so the most of that is new, new headgasket.

so im thinking then im burning oil through the piston rings? maybe the motor is just getting old and worn? i literally did an oil change only about 900 miles ago and i lost a quart already. i havent been driving like a maniac either.

[kevos2k]

i havent been driving like a maniac either.

this could be the issue... have you considered driving like a maniac man ??? lol

[Geo02s2k]

this could be the issue... have you considered driving like a maniac man ??? lol

Y'all laugh, but I had this same experience about 6 months ago. I hit vtec and, in the light from the setting sun behind me, there was a cloud of smoke. One track weekend seems to have cured it, though. Still need to add a little oil between changes, but not as much as before hitting the track. :shrug:

[Domino]

Check your PCV valve

[repiv]

Let's take a look at some possibilities .........................
The smoke you saw behind you may have been oil or it may not have been. Only someone following you can make such a determination. Rear view at night is not a good observation. It may have just been a lot of carbon buildup in the exhaust system getting blown out from the sudden rise in rpm as what happens when you prepare to pass someone at highway speeds.

I'm sure your observation of the oil level was correct, but before you think you've burned a qt. of oil in one month, can you tell us if you checked your oil level "cold" within a day or so after that oil change? Most people who do their own oil changes can attest to the fact that if you fill it to the "full" mark, as soon as you start the engine the oil filter purges itself of all the air. This can take up to over 1/2 a qt. Therefore, you may have only used less than 1/2 qt. from a month ago. Next, how many miles has it been in that month. If you've only driven a few hundred miles, it might be time to worry. If you've driven 1000 or 2000 or 3000 miles in that time, that is not unusual.
The oil pressure light is an indication of a predetermined threshold of oil pressure and does not always directly relate to oil level or quantity. You can keep the oil pressure light off with as little as 2 qts of oil in the crankcase. That is to say, you can leak 3.5 qts of oil before the oil light will even think about coming on. They don't call it an "idiot" light for nothing.

Bad valve adjustment doesn't burn oil. Bad valve seals DO and this doesn't always have anything to do with valve adjustment. Although there are many complex factors causing oil consumption, an "old timers" rule of thumb was that if you smoked when accelerating hard, you were getting oil past the rings. If you smoked when you were engine braking hard, oil was getting past the valve seals. Remember, that's just a rule of thumb and can't be used as gospel. Only a compression and leakdown test can prove one or the other.

As already mentioned, oil can disappear by getting past bad rings or bad valve seals or past the PCV valve. Replacing rings is a big, expensive job. Replacing valve seals is not so bad. Putting on a stronger PCV valve (like from a Toyota Supra or a Krankvent) may solve that (weak OEM PCV valve). If you are losing a lot of oil out the front valve cover breather, there's not much you can do about this without having a detrimental effect on engine function (like putting a KV on that front breather for example). Putting a catch can won't stop the oil from disappearing, just stop it from going back into the combustion process.
Oil can also escape out the rear main engine seal but since you've indicated you see no leaks under the car, this is a remote likelihood.

Before you go off and spend a ton of money getting this and that "fixed", double check your oil consumption for another month, beginning with a "full" dipstick reading (top it up). Then you will know for sure how much you are losing.
If it is really getting used up, then consider a compression and leakdown test before assessing your options.

130K miles is not unheard of but this is starting to become a "geriatric" motor. The fact that you had to get head work tells me that the damage may not have been confined to the head. Piston and cylinder damage may have accompanied the head damage, which may still not be fully resolved with the work done so far.

[hankooks2k]

well it was only 900 milles in that month that i lost the oil.

if my pcv valve is bad, cant i just replace it with a new oem pcv valve? id rather not go the krankvent route just because of the reviews i hear that when people take off the krankvent then the blowby from the rings is even worse.

after i did the oil change i did check it after one day and it was indeed at the Full mark. i dont think it would be the valve stem seals because those were replaced as well, but again you never know.

[repiv]

900 miles and nearly 1 qt is somewhat of a concern. A local S owner got an engine rebuild out of it for burning about that much.
The OEM PCV valve is a very weak valve and not your best choice if oil consumption is as bad as yours. A replacement valve may not be your answer but it's worth a try. However, the Supra PCV valve is your better bet. It's only a few dollars compared to the 80 bucks of the KV.
If you've got new valve guide seals, then I suspect your problems are below the head. Again, a compression and leakdown would be well worth the time and expense.

[hankooks2k]

yea ill be looking to do a compression test and leakdown test to narrow it down. Thanks for the feedback xviper!

[griffon]

Now that your valves are sealing tight you are having blow-by issues with the rings.

I have seen this happen before in other types of higher mileage engines where a valve job was done with out regard to the pistons and rings.

[alltech.magoo]

good info

[Jasonoff]

900 miles and nearly 1 qt is somewhat or a concern. A local S owner got an engine rebuild out of it for burning about that much.
The OEM PCV valve is a very weak valve and not your best choice if oil consumption is as bad as yours. A replacement valve may not be your answer but it's worth a try. However, the Supra PCV valve is your better bet. It's only a few dollars compared to the 80 bucks of the KV.
If you've got new valve guide seals, then I suspect your problems are below the head. Again, a compression and leakdown would be well worth the time and expense.Quick question. How would a new PCV help prevent oil loss?

It's a one way valve. It 's only "supposed" to block flow from the intake to engine. It allows flow in the other direction which is the way that could burn oil.

[bimdub]

Quick question. How would a new PCV help prevent oil loss?

It's a one way valve. It 's only "supposed" to block flow from the intake to engine. It allows flow in the other direction which is the way that could burn oil.

it could be worn and no longer stopping the reverse flow!

[Jasonoff]

it could be worn and no longer stopping the reverse flow!Wouldn't that prevent blow by because of the positive pressure it would create in the crank case? Also if that was the case his dipstick wouldn't stay seated either.

[repiv]

Replacing an OEM PCV valve with another OEM one may not do much if blow by is a real problem. Putting in a stronger one might. On a NA engine, the intake manifold is under constant vacuum, thus always drawing vapours through the PCV line. A stronger PCV valve will make it necessary for vacuum to build up (like during hard engine braking) before pulling vapours through. The front breather will still allow crankcase pressures to escape, so sometimes, even replacing with a stronger PCV won't help.
Dipsticks have been known to pop out even for NA applications but is more often seen on F.I. engines. This depends on the extent of the pressure build up. Mine has never popped out. It's more evident in those engines where the dipstick doesn't fit well in the dipstick hole. Replacement of one or the other generally fixes this.

[Jasonoff]

I use a PCV from a Toyota supra inline with the OE PCV.

[Hondassport]

the mod below fixed my oil consumption:
http://forums.s2kca.com/showthread.php?t=13605&page=4

[Jasonoff]

nice link. Makes sense.

[hankooks2k]

so i had to fill up a quart in mid september, and now its about november, ive lost about another quart. and i drove about a good 1200 miles. so im still losing oil somewhere. im going to do the supra pcv valve and see how that works. i was doing a little bit more reading about it, would going to an ap2 valve cover help possibly? because of the fact that the pcv valve is not angle vertically into the valve cover rather its angled horizontally to prevent oil suction on the top baffle of the valve cover

[repiv]

so i had to fill up a quart in mid september, and now its about november, ive lost about another quart. and i drove about a good 1200 miles. so im still losing oil somewhere. im going to do the supra pcv valve and see how that works. i was doing a little bit more reading about it, would going to an ap2 valve cover help possibly? because of the fact that the pcv valve is not angle vertically into the valve cover rather its angled horizontally to prevent oil suction on the top baffle of the valve cover

Cost wise, the AP2 makes no sense. You'll have spent well over 200 bucks for something that most likely still won't change anything insofar as oil getting tossed out the PCV valve (if that's what it is). A Supra valve costs 10 bucks.
As far as direction of entry of oil, I doubt this aspect makes any difference. The height of each entry point is not that different and oil would have an easier time getting into a horizontal entry (like on an AP2).
The Supra PCV is a cheap experiment. With that kind of oil consumption, I suspect you've got far bigger problems than just the PCV, but it's worth a try for a few bucks. The only other S2000 that I personally know of and had that kind of oil usage, needed new rings and liners. That one was a friend's and he was going through oil at a rate of about 1 qt. every 800 miles. Honda warranteed it and his engine has been running fine ever since.

BTW, Did you ever get that compression and leak down test done. That would be the next move before you have the engine torn down.

[hankooks2k]

hmmm yea sounds like the ap2 vc wouldnt have too much of an impact, i took the pcv valve off and tested it and it works fine. i could always try the supra pcv but i dont see how it would affect anything if the oem is working ok.

i havent gotten a compression or leakdown since i got the head rebuilt so im going to get one here soon before any major work. I'll report back after i get that done, ill have that done here maybe on friday since i have the day off. I wish i had warranty :(

[hankooks2k]

quick question. if i were to do the rings, im going to do the work myself. Ive taken apart the top end of the car easy, the head, doing valve adjustments, cams and what not, and we just had to swap a motor TWICE in my friends s2k. so im pretty familiar with everything on the s2k. the only thing i havent done is take apart the bottom end. To replace rings, after i take off the top end and what not, would i just drop the oil pan, unbolt the rods and push the piston out through the top end of the block and replace the rings?

[repiv]

i dont see how it would affect anything if the oem is working ok.
I think you're missing the point. The Supra PCV valve is a much stronger valve. It might provide just enough resistence to opening that it could reduce your oil consumption to the point you could live with it. Isn't 10 bucks worth the try? On the other hand, if you're just dying to tear your engine apart, then by all means, you can rationalize the PCV valve out of the equation.

As for doing a ring job, it's best you have a manual. Getting instructions over the net is a poor substitute and you could end up with an engine that's got far more serious problems.

[hankooks2k]

I think you're missing the point. The Supra PCV valve is a much stronger valve. It might provide just enough resistence to opening that it could reduce your oil consumption to the point you could live with it. Isn't 10 bucks worth the try? On the other hand, if you're just dying to tear your engine apart, then by all means, you can rationalize the PCV valve out of the equation.

As for doing a ring job, it's best you have a manual. Getting instructions over the net is a poor substitute and you could end up with an engine that's got far more serious problems.

i understand its a stronger valve, and id be willing to try it, but again like you said yourself, this much oil consumption would probably be more than a pcv valve. i never said i would just forget about the pcv.

as for the ring job, i was just asking IF i had to do it, i am not looking forward to doing this type of work on the car. I do have a manual and i would obviously use it I was just asking for a general how to. I understand its more complex than that, but ill get the compression and leakdown done so that way i can narrow down the possibilities.

[hankooks2k]

just did a compression test

1. 195
2. 190
3. 187
4. 199

again car has 130k miles on it

also i put some oil in some of the cylinders and it increase the psi by about maybe 5-10

sound like it could be the rings? also i went and bought a supra pcv, it was only 4 bucks and will be trying to put that on tomorrow

[bimdub]

just did a compression test

1. 195
2. 190
3. 187
4. 199

again car has 130k miles on it

also i put some oil in some of the cylinders and it increase the psi by about maybe 5-10

sound like it could be the rings?

I tried to look this up...but alas I failed.......however, I see less than 5% from the highest to the lowest.....and you are only gaining 5-10 wet......this is not a lot...you should gain something wet even when everything is new. I would normally not suspect rings, I did think the compression pressure should be higher overall though.......like in the 225 range?

did you do this test with the throttle opened fully? its very important to ensure complete cylinder filling.........

I would also look into a leakdown test.......I suspect the valves or headgasket may be more of a problem than the rings?

repiv? the question is now.....what is the range of compression pressure on the S2000?

[repiv]

repiv? the question is now.....what is the range of compression pressure on the S2000?

"Book" says nominal is 228.

[hankooks2k]

I did not do the compression test with a open throttle. Could that be why they are lower numbers? I'll be trying a leakdown soon. If it was a headgasket I would have oil in coolant or coolant in oil....right?

[repiv]

Do it WOT.
Depending on where the head gasket break is, you may or may not see one fluid in the other. If you have a break between the cooling jacket and an oil passageway, then you'd see intrusion, but this wouldn't necessarily make for low compression. The most readily seen blown head gasket problem is where coolant is getting into the combustion chamber and the car blows clouds of white smoke.

[bimdub]

yup, you do the test WOT and report back, I am thinking you are not going to find much wrong, you probably just need to go with the pcv swap.....from what I am reading you are concerned about oil loss, but the engine is probably not anywhere close to "worn" out.....are you sure the oil is getting burned? evidence on the plugs? blue smoke out the tailpipe? ect....

also I have experienced a fluke with a friends Hyundai that consumed oil at a very alarming rate! nearly 1/2 quart every 100 miles....and with only 20K or so miles on it.......it turned out to be the valve guides.....but since the cat is so efficient there was literally no smoke ever! the sad thing is the car was repaired under warranty only to have the cat take a ~~ a few months later.......go figure...they should have thought of that when they did the service.....

you could be experiencing a similar issue?

[hankooks2k]

yup, you do the test WOT and report back, I am thinking you are not going to find much wrong, you probably just need to go with the pcv swap.....from what I am reading you are concerned about oil loss, but the engine is probably not anywhere close to "worn" out.....are you sure the oil is getting burned? evidence on the plugs? blue smoke out the tailpipe? ect....

also I have experienced a fluke with a friends Hyundai that consumed oil at a very alarming rate! nearly 1/2 quart every 100 miles....and with only 20K or so miles on it.......it turned out to be the valve guides.....but since the cat is so efficient there was literally no smoke ever! the sad thing is the car was repaired under warranty only to have the cat take a ~~ a few months later.......go figure...they should have thought of that when they did the service.....

you could be experiencing a similar issue?

When i pulled the plugs, they were a little white. ive never seen blue smoke out the exhaust.

hopefully if it has anything to do with the head itll just be replaced/fixed under warranty from the shop that did it, id rather it be the head than the rings. or even better just the pcv valve :thumbup:

ill do another compression test at WOT and get the numbers.

[mad frog]

I am follwing this thread with MUCH interest, given that my car is experiencing the exact same issue: 1Qt/1200 Mi.

[Domino]

a little white is ok, atleast from what i've seen from mine

[jjwalker]

I am follwing this thread with MUCH interest, given that my car is experiencing the exact same issue: 1Qt/1200 Mi.

I thought this was normal for ap1?

[hankooks2k]

1qt in 1200 miles is NOT normal.

assume you do your oil change every 5k miles with a synthetic, that means before you change your oil you just refilled 4 qts....thats not normal

[repiv]

a little white is ok, atleast from what i've seen from mine
Don't confuse the white vapour you would see from the exhaust tip when the weather turns cold. This is just normal exhaust system condensation becoming visible as it hits the extreme temps outside. Normally, this is seen when temps get below freezing outside but is dependent upon things like barametric pressure and relative humidity. You can see this vapour just above freezing temps in some places, while in other places, you might not see this till it gets way below freezing. This is the result of the normal combustion process, which results in H2O production on the right side of the combustion chemical reaction.
A blown head gasket that produces white smoke will do it regardless of outside temp and will also have a sweet smell, as the coolant is being burned up. This is the result of ethylene glycol (sweet smell) and H2O (steam) being introduced into the combustion process.
Where one is normal, the other is not.


I thought this was normal for ap1?
It can be "normal" for some AP1s, but only during the break in process, which can take as long as 15K to 20K miles. The vast majority of AP1s will either reduce their oil consumption drastically or stop all together after that. If it continues after break in and oil usage is around 1 qt per 1000 miles or less (miles), this would be of some concern and further investigation into why, is in order.