Car eats oil - oil change interval?

Car eats a quart of oil every 300-400 miles (ran it low on oil a few years ago.) Ive just been adding a quart of 10W30 (hi-milage) every week or so. (I dont want to spend the big $$ to get it fixed, so Ill just keep driving it for a while longer, then sell it what whatever someone is willing to pay.)

Now, giving the oil consumption rate, Ive been adding several quarts of oil between oil changes, and so, if you think about it, the engine always has pretty fresh oil in it :) So, how often should I be taking it in for an oil (and filter) change? Use a less frequent interval? Or perhaps the regular interval because the filter is getting extra dirty.

TIA Bubba

Sounds like your oil is being changed continuously so no need for an "oil change" though I would change the filter at whatever the recommended interval is for the car event though the oil going through it is cleaner than in a non-burner.

so is the car eating the good oil or the bad oil equal quantities of each? Its probably eating the good oil. I would say change the oil and filter every 2,000 miles or so.

The oil is mixing together--- and why would you recommend changing it so frequently? It's barely dirty at 2000...

Are you sure? I suggest that you for oil analysis. If the reason for the excessive oil consumption is worn rings, then chances are you are getting a lot of blow-by, which is putting a lot of combustion products in your oil (water, unburned hydrocarbons, soot, etc.). If this is the case, the stuff in the crankcase is very marginal after a few thousand miles. An oil analysis will let you know. If the oil consumption is not related to worn rings, then I think you might want to investigate having it fixed....

Ed

I have a '94 CV that uses a qt every 6-700 miles. I also have a very scientific oil change interval that has worked wel for the las 150k miles - it is now pushing 300k, runs good with no visible smoke, no leaks, and good oil pressure, power and fuel mileage. I buy a 12 pack of cheap 10w30 oil where ever it may be cheapest that weekend along with a name brand filter that I am not too particular about. I use 5 qts to change it, throw a couple in the trunk to add up every other gas fillup. When I have used the 12 pk and it needs another qt, I start the routine over again. I thought the SOB would have died by now but, it just keeps lumbering along toward 300k and then, I suppose, 400k at this rate.

Lugnut

You need to find where the oil is going. Leaking it is one thing, burning it is another.

That's not TOO much different than me and my '82 Mazda 626 with 197K on the meter - I've been running Delo 400 15W40 in it for years - The stuff is intended for diesel (specifically semi and bulldozer) applications, but after doing some research, I found out that it's well above spec for practically any engine application you want to put it to. For a long time, I had a connection at a local truck stop where I could get it for $8/gallon jug (versus the "general public price" of $17 and change) so I'd buy it 3 gallons at a time.

I do an "official" oil change using a decent filter, and filling it with a gallon and a half. The half gallon that's left over goes into a nifty little space under the hood that holds the gallon jug like it was custom-built for the job, and the third gallon goes in the trunk. Every fill-up, or as often as I think to check, I top up to full as needed from the jug under the hood (or move the jug from the trunk), and once I've gone through the 3 gallons, I do another "official" oil change to start the cycle again. Generally, that means somewhere between 4800 and

Like yours, it just keeps going, and going, and going, and...

C'mon Ed...You know that car is not worth the price of a GD oil analysis? Who are you trying to put on ;>)

No oil leaks. My mechanic says the oil is burned in the catalytic converter.

You should anticipate having fun at your next state inspection ;)

It passed emissions test a year ago, and it had been eating oil for two years. Next emissions test is in 1 year :)

Then the engine has internal issues of one degree or another. Unless you track down the specific causes of the oil getting/remaining in the combustion chamber you may not want to count on it as being a 'self changing' system as oil is added to make up the difference.

Car eats a quart of oil every 300-400 miles (ran it low on oil a few years ago.)

Below the double lines, it would seem apparent that the rings are worn out on this car. It wouldnt HAVE to be the piston rings, but that is the most common reason for lack of oil control like this.

And, nothing will fix it other than a motor overhaul or replacement.

You may be able to drive it for a long time (until the thing just breaks down, or the emissions test sends you to the garage, or until the catalytic converter gives up, catches on fire, or allow smoke so badly that a policeman pulls you over) by adding fresh oil to keep her topped up.

I would change the filter, I guess, every 3-5000 miles because there is likely to be carbon or metal particles in the oil, and you may want to drive it as long as you can. Particulates will eat away your bearings and oil pressure will eventually get so low the car will self destruct, and an oil filter is pretty cheap.

This is a sad story. Toyota makes a pretty good engine, in most cases.

Yup. Also, I'd try something thicker than 10W30; 10W40 or 15W50; to see if that slows the oil burning.

No worries about that now. Given a choice you want to buy oil filters with the greatest capacity. But it really doesn't matter. Your engine won't notice.

Intuition says that since you add so much oil, the oil is always fresh.

The truth is that an engine so unbelievably worn out (especially in this day and age with only 140k miles) as to burn a quart in 300-400 miles is also blowing HUGE amounts of combustion byproducts into the oil, so that the oil is contaminated at a rate many times faster than a healthy engine.

I agree, and I'm also guessing that the car has reduced power and mileage and really low compression. I'd do a compression test to see if maybe there is a problem with one cylinder and maybe you have a bad gasket, or something. But that's only if you are lucky. I'm guessing that it needs to be rebuilt, or a ring job at the very least.

He said that the cause was he ran it low on oil several years ago. The damage that is causing high oil consumption is probably to bearings, crank, rings, and cylinder walls. Given the other information he gave, it makes no sense to rebuild ( there is no way rebuilding will increase the value of the car by more than it costs) and there is no reason to believe the engine won't last a long time in it's present condition if it is driven sensibly and the oil is changed frequently. Since it passes emissions tests, it probably gets good gas mileage and if he isn't interested in winning any races the performance is probably more than he needs. I would do like someone else suggested-> Buy a case of oil (12 in a box) and filter, then change the oil and filter and add oil as needed. When the case is used up do it all over again. It would be a good idea to use at least 10-40 in the summer and go back to 10-30 for the winter.

-jim

----== Posted via Pronews.Com - Unlimited-Unrestricted-Secure Usenet News==----

---= - Total Privacy via Encryption =---

Maybe it needs a ring job. cuhulin

there's no evidence a heavier grade of oil gets burnt slower. in fact, the flash point of heavier grades is often lower.