SillePimp

i have a '97 gxe auto and it seems like i'm losing oil. i just switched to mobil 1 10w30 synthetic blend about 3 weeks ago along with a new oil filter. i checked the engine oil level on a flat surface yesterday and it dropped quite a bit from the last oil change i made. does anyone else have this problem? or do i have an engine problem that will result to serious damage if i don't get it fixed?

Mishmosh

iTrader: (3)

I recently switched to Mobil 1 5W30. Don't have any problems. Just make sure no oil is leaking from the plug or the filter. Also, check the pavement where you park your car for possible oil.

max808

Sound like you are leaking, check you garage or under your engine for dripping. If your drain plug is leaking I'd consider yourself lucky. Also, maybe the drain gasket may be flat, get one those are cheap (under $1). I think Nissan recommends changing every 3-4 oil changes.

vmok

some more food for thought.

make sure you're checking the oil at the same conditions.

if you check the car after it's sat over night vs. checking it at the gas station right after getting off the freeway.

as oil heats up, it expands, so it may read higher than when it's cold.

however, after the car has sat overnight, all the oil in the engine has dripped to the bottom of the pan, so the level can read higher when the car is perfectly cold.

then there's all the in-betweens.

so you may want to check in the morning before you start and reference it to that.

i noticed that both my '96 auto and my 97 5sp both take about a quart between oil changes (3000-5000 miles).

-V

Daniel B. Martin

Are you sure?

max808

One quart of oil between changes sound like there's a leak somewhere. I guess the cost of 1 quart versus repair may be cost effective.

Sonic

AFAIK, fossil oil kinda congeals to a small degree, sealing small gaps in seals in your engine block. Synthetic doesn't do this. The oil is now free to seep into the cylinder and be burned in small amounts. This may account for the oil 'disappearing'

vmok

that makes sense... I'm using Mobil 1 15w50...

-V

vmok

I thought it was normal because both the 1995 Maximas my parents had, the 1996 I had, and the 1997 I have now all use about a quart between changes... maybe we got stuck with all the lemon engines (or at least the ones on the far end of the tolerence specifications!)

-V

Sonic

Oh, and in high mileage cars and brand new cars, losing a quart of oil is not unheard of, though I didn't seem to lose more than 1/2 a pint during my last oil change.

SillePimp

There is no leak from the drain plug or oil filter. And yes, I've checked the level this past weekend and it was parked in the garage for two days. That should be enough time for the oil to settle. May be I should also mention that I am using Bosch Platinum plugs. Could that be the cause? And I also do a lot of 1-2, 2-D shifting during my daily commute to work. Thoughts, comments, and suggestions please!

vmok

135,000 miles count as high (that's the '97)
213,000 miles (in the 1990)...

-V

Sonic

Like I said, a 'bit is normal'. Since you can't quantify how much you have lost wiothout draining the oil, it may be completely normal. Also, note my post above about changing from fossil to synthetic.

vmok

Nope, not at all. I'm not sure because I'm not the expert...

However, according to what I've read, it seems that hot oil expands. Below are links from ehow.com and vintagecars.com. Check point 1 in the ehow article and point 2 in the vintage car article.

http://www.ehow.com/eHow/eHow/0,1053,103,00.html

http://vintagecars.about.com/autos/v...htoilcheck.htm

I've also read (but can't find and therefore can't substantiate at this time) that most dipsticks are calibrated for cold (so you don't burn yourself while checking the oil, and also the conditions are more controlled because all the oil has dripped back into the pan). On the other hand, I've read Ford in particular has calibrated their dipsticks to be accurate while hot (because most people who checked their oil checked it at the gas station while filling up gas, while car was still hot). Which one is right? I don't know, depends on the vehicle. Check the manual .

-V

SillePimp

How many miles do you have in your car? I'm approaching 80k. May be I should take the same route...

deezo

iTrader: (3)

Sonic

I currently have 90,735 exactly.

Daniel B. Martin

Thanks for two good references. I always thought that gases expand when heated and liquids don't. Better brush up on my physics!

Jeff92se

iTrader: (82)

Daniel, everything expands when hot right? So if the engine block etc. expands at the relatively same rate, wouldn't that affect the oil level also? I think the main thing when checking your oil level when the car is hot(ie.. just turned off), the oil coating the inside of the engine has not had a chance to drain back into the pan. IMHO, that would seem to have a greater affect on engine oil level than the temp of the oil. Unless you are talking about very extreme temps that we don't really see. I would say (opinion) if you measure you oil level immediately after shutting the engine off vs waiting 20 minutes, there would be up to a 1/2 diff. in level readings. That difference is probably much greater than any difference in the oil's temp expansion. If it is not, I would have a big problem regarding the oil's ability to flow thoughout the tiny oil gallies modern engines have. Have you seen an the oil feed gallies to the cams, chain tensioners etc..? Very small orifices indeed.

Daniel B. Martin

Yes, but not at the same rate. Each material has it's own Coefficient of Thermal Expansion. See the table at http://www.handyharmancanada.com/The...k/comparis.htm It shows that Zinc (at the top of the table) expands at a much faster rate than Carbon (at the bottom of the table).

According to http://www.astro.columbia.edu/~tao/C...roblem/04.html the CoTE for engine oil is 10**-4 per degrees Kelvin. I don't understand enough of the physics to compare that to other materials. Who is our resident physicist? Is it Chris J. Vurnis?

TarHeelMax

No, I'm not the resident physicist. And no, not everything expands when hot. Remember that water is densest at 4 degrees Celcius. That means that as you're melting a block of ice, the volume of that water is actually decreasing until it reaches 4 degrees, then the water expands again.

At the temperatures we're dealing with, an engine block is a solid so the atoms comprising it are "locked" in a lattice structure. M-oil is a liquid whose atoms are in perpetual motion, colliding frequently with neighbors. Because of this property, the volume of a liquid is inherently more responsive to changes in temperature (energy). DBM's website states the coefficient of thermal expansion for aluminum and its alloys is from 2.1 to 2.5x10E-5 mm/mm per degree Celcius. DBM also tells us that the CoTE of m-oil is 1x10E-4 mm/mm per degree Kelvin. The liquid m-oil has a four-fold higher CoTE than the solid aluminum alloy! (BTW, there is no difference between Celcius and Kelvin degrees in this case since they are the same scale with different zero points)

The point of all this, is that the oil shrinks and expands more than the engine block over the same temperature range.

SillePimp, as long as the oil level is within the hatched area of your dipstick, I don't think you'll incur any engine damage. Is your car running well? Is your engine's NVH different now than before you changed from dino m-oil to synth blend? DBM, could it possibly be a broken piston ring and if so, what are the symptoms? Your best bet is to monitor your oil level carefully over the next month or two and see whether there is additional loss. If there is, and you're still not leaking, then you're burning it.

vmok

I've learned my lesson from you... be sure you can substantiate before posting ...

i.e. even if you say you can do 1/4 mile in 14.0s, be sure you can substantiate with a scanned time slip.

-V

Daniel B. Martin

SillePimp (who originated this thread) did not quantify the rate of oil loss, nor did he mention other familiar oil loss symptoms such as wet spots on the pavement below the engine or blue smoke in the exhaust. I hesitate to make a guess about his engine with so few clues.

A broken piston ring... the consequences depend on whether the ring is a compression ring or an oil ring.

Broken compression ring -- increased fuel consumption, loss of power, increased blowby, "gunge" collecting in the engine air intake ductwork and throttle body.

Broken oil ring -- oil consumption, blue smoke in the exhaust, failing Oxygen Sensors (crusted with oily residue), clogged Catalytic Converter (oily residue).

SillePimp

[QUOTE]Originally posted by Daniel B. Martin
SillePimp (who originated this thread) did not quantify the rate of oil loss, nor did he mention other familiar oil loss symptoms such as wet spots on the pavement below the engine or blue smoke in the exhaust. I hesitate to make a guess about his engine with so few clues.

A broken piston ring... the consequences depend on whether the ring is a compression ring or an oil ring.

Broken compression ring -- increased fuel consumption, loss of power, increased blowby, "gunge" collecting in the engine air intake ductwork and throttle body.

Broken oil ring -- oil consumption, blue smoke in the exhaust, failing Oxygen Sensors (crusted with oily residue), clogged Catalytic Converter (oily residue).
/QUOTE]

The only leak I've seen on the driveway or the garage is coming from my transmission and power steering hoses. I recently had the ATF changed at AAMCO and I don't think they did a good job with the gasket. I'm taking it back this weekend to have them redo it and also schedule an appointment with the dealership to have them perform the recall on the power steering hose leak. I haven't checked the throttle body yet. This oil problem started when I installed my WSP Y-pipe. However, gas mileage or efficiency is still the same (24-26 mpg stop and go driving on the freeway and streets). Also, does the car have a low oil pressure warning that pops up when it's detected? I don't know the answer from the top of my head.

Analysis of my engine oil after changing it three weeks ago:
After 1 week of driving ---> level was exactly at the maximum point.
After 2.5 weeks of driving --> level is approximately 1/8 inch below the maximum point.

I hope this helps.

Daniel B. Martin

I'm sure you intended to be helpful, but this isn't the right information.

Oil consumption is measured in terms of miles per quart. How many miles does your car travel before you have to add a quart of oil?

Does your exhaust have blue smoke?

SillePimp

No visible smoke out of the exhaust.

SillePimp

No visible smoke out of the exhaust.

zaebis

Well first of your oil level is measured at normal engine operating temperature, not after 2 days in garage, at sea level or anything like that. Oil expansion may be significant to account for a loss. If you look at your dipstick you will see cold and hot marks (notches) with approximately 1/2 inch in between. On your dipstick you have HOT mark so your oil must be there when you measire it.

If you see your oil level drops on hot engine then:

1/ it is leaking (with visible signs under the car or on the engine)

2/ you are burning it (check cylinder compression)

about 1/2 quart per 3500 miles burn is normal. I would also suggest you dont do 1-2,2-d shifts. Nothing to do with oil leak but your tranny may be worn prematurely.

Sonic

About how many miles was this? 100, 500, 1000? Secondly, the oil light that you see is more of an 'oh ****' light. It only comes on when you get to the point that the oil pressure is so low that it is dangerous to continue driving the car. When that light comes on IMMEDIATELY pull over, shut the engine at at least put 1 quart into your engine. Secondly, again, I ask, you did change from fossil to synthetic, didn't you?

SillePimp

Recently switched to Mobil1 10w30 synthetic blend. I've used Castrol synthetic blend for the most part (up to 77k miles).

frougier

Daniel, you might be thinking of liquid being incompressible. All substances do expand with heat (matter is excited at high temperature and will occupy a greater volume) think of an alcohol thermometer...
However this guys loss can only be attributed to a leak. I don't think a quart is attributable to expansion...

Daniel B. Martin

Right on all counts! There are a very few exceptions to the expansion rule, such as water expanding as it cools from 0 to -4 degrees Centigrade. That's one fo the reasons water-cooled engines need anti-freeze.