Oil issue on 1996 Toyota Tercel.

If you catalytic convertor is working, you are not likely to see any smoke if you are only buring a quart per thousand miles.

On the other hand, it only take a relatively small drip to use a quart per thousand miles. If it is the rear seal that is leaking, then you might not see much, if any, oil in your drive way.

If you don't trust your mechanic, find another one, I would not be very impressed with a mechanic that overfilled the engine even once. However, a minor overfill should nto cause any problems (minor being less than 1/2 a quart).

If it was my car, I'd look for leaks. If I found done, I'd just drive it. A quart of oil per thousand miles on a car of that age is not that big a deal. My Sister's Honda burned that much for 5 years and she never had a problem. Just be sure to regularly check the oil level.

Ed

I had a 92 Tercel LE that started to loose oil after about the 100,000 km. I began to notice it during winters when my dealer used lighter weight oil. When the dealer switched over to using 5w30 year round the oil loss became much more apparent. As I started to drive less, it seemed to loose just as much or more oil between changes. The most I ever lost was a liter or so between changes.

There were never any oil stains on my drive way or visible leaks under the hood. My exhaust wasn't blue, but it appeared cloudy at times.

Your problem with over filling can cause serious problems. The motor oil could get foamy and not lubricate properly, and may even affect your oil seals due to increased pressure.

I agree with your mechanic, you are burning oil, not leaking it. If you were leaking a quart per 1,000 miles, it would be all over the place. Well, it would at least be more than a drop hanging from the transmission cover.

If the inside of your tailpipe is black, this is a sign that you are burning oil.

To make a small Reality Check, a quart per 1,000 miles is a quart every third trip to the gas pump.

A quart per 1,500 ~ 2,000 miles is not cause for alarm. A quart per 1,000 miles was considered reasonably normal consumption once upon a time. By definition, an engine that is burning oil is consuming it through the internal workings, oil that appears on the outside of the motor is leaking oil, not burning oil. A main seal will create a leak to the outside that will form pools of oil everywhere you go. Worn rings or valve seals will allow small amounts of oil into the combustion chamber where it will be physically burned along with the fuel, and the result will sometimes be a black residue on the inside of the tailpipe. I'd not expect you to see any visible smoke coming out of your car under most conditions. I'd not expect you to see smoke from your own car while you are driving it under any conditions. The only time anybody would see smoke at the rate you are consuming it is if they were following you and observed you agressively downshifting. This could pull enough oil, theoretically, to saturate the exhaust to the point that smoke would be visible. If you drive like an old woman going to the market or church, AND your oil consumption lessens, then you have bad rings or valve seals. Valve seals are not expensive to replace, nor is it a particularly difficult job. The problem you have is that you are not a mechanic, so you have to pay somebody that is.

This is the same guy that overfilled my oil by almost a full quart twice.....;0) But, your observation & his (the owner now, not his lush mechanic) may be correct after reviewing some of the replies here.

I did look inside the tail pipe. The muffler is about 1 1/2yrs old, but the problem I have is I wouldn't know what was normal or abnormal, but you are correct I did look and it is black.

I never drive my car like an old lady so that would be a practice I'd REALLY have to practice.......(LOL)

I still can't get an explanation for the smoke I seen SPEW out on the highway twice after they overfilled my oil & than it mysteriously stopped after I level it. Everyone keeps saying I won't see smoke. I guess its not that important. I just wish I can definately determine if I'm burning oil, my mechanic seems to be a bit lazy (the owner as well) to give me a definate answer. If I can fix it before it worsens where its just seal replacements than I'd like to do it. This car STILL has a lot of life left in it even though its 14yrs old......;0)

Thx for your help.

Is a rear seal expensive to fix if that's the case?

There is that matter of the droplet I see that is VERY visible underneath. I believe it works its way down and forms at the point right under the tranny. I personally don't know where the rear seal is but I'll try & get a schematic.........;0)

Thx fer yer help Ed.

I caught it BOTH times quickly enough I think. But seeing that smoke SPEW the way it did going on an upgrade was kind of nerve racking......;0)

Thx fer yer help.

What I said (or meant to say) is that if your car is burning a quart of oil per 1000 miles, you wouldn't expect to see oil smoke - espeically after the car was warmed up. An overfill condition that somehow resulted in a sudden surge of oil into the engine would be a different matter. I can't imagine that a minor overfill would cause a problem, but then I don't know how overfilled the car was. The most likely senario to casue a sudden plume of smoke would be for a significant slug of oil to be drawn into the intake through the PCV system. Minor puffs of somke when shifting would make me suspect the valve guides / valve guide seals. Continuous blue smoke when underpower (like going up a hill) would make me think worn oil control rings. Light blue smoke at idle is likely the valve guide / vale guide seals (but maybe also worn compression rings). Still, at only a quart per 1000 miles, I'd just dirve the car. It might be worth trying one of the high mileage oils like Valvoline Max-Life. It is "claimed" to include special ingredients that soften and partially restore the performance of seals. I've never used oils like this, but I figure it couldn't hurt to give them a go. See

Ed

I'd expect the smoke to spew forth during an active over-fill. But that would be a temporary condition until the oil attained a normal level.

There is a chance that overillling would push the oil pressure beyond acceptable limits that blows a front or rear main seal, but this would be a fatal condition for the respective seal, so there would be oil hanging all over the place before it pooled in your driveway. Since you have no pool in the driveway, then your seals are intact.

The valve seals do not seal pressurized oil, so any oil that gets past does so merely by dripping. By definition, the drip will be small so the consumption rate will be low. Odds are high that you would never see smoke from oil that gets past a leaky valve guide/seal. To be sure, a seal can have a catastrophic failure that can allow enough oil to get past that you see smoke, but as a practical mater this hardly ever happens, and the consumption rate would be much greater than you are reporting.

If you could drive like an old lady for a month or two and avoid downshifting that forces high RPMs to slow your car, AND this reduces the consumption rate of your oil, then I'd be thinking a ring job is in order. High vacuum that comes from high speed downshifts can cause oil to be sucked past valve seals, so there's a chance rings aren't the problem. But if you drive like an old lady for several weeks and the oil consumption is reduced, then you have a clue as to the problems.

Frankly, if you can stop the oil consumption by changing your driving style, then I'd simply pour in a quart as needed and forget the whole issue. Keep driving the way you drive, knowing that it causes you to use oil. I'm not sure this is a good way to treat an econobox, but you can pour in lots of oil before you spend what it costs to do a ring job.

Ed White's post is probably the most likely to answer your question.

If the oil is leaking externally and ending up on the transmission housing, it might just coat the undercarriage. If the undercarriage feels oily, it is just clinging there.

Look for a puff of smoke on startup. If there is, that is a sign of leaking valve guides, and the most likely scenario in this vintage Tercel. Replacing valve guides is not that difficult but it is labor intensive.

Leaking rings are not so likely in 128,000 miles. This can be checked with a compression test. If the rings are leaking, I'd just keep adding oil as a ring job is pretty expensive.

A leaking rear seal would require removal of the transmission, and this is not a likely problem anyway with that mileage.