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None of my cars ever used 1qt of oil per 1,000 miles. That kind of usage and air pollution is not normal and given the current antipollution laws, I doubt it would even be allowed on cars less than 20 or 30 years old.
 

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The problem is as far as smog there is no regulation for oil consumption and a car that burns oil to a point anyway can pass smog. If you ever run into an oil consumption issue under warranty the dealer will monitor the consumption. If it's 1 qt or less per 1000 miles they will tell you the consumption is acceptable. I strongly disagree, but that is what they will tell you. If it's not smoking chances are it's a small crack in the ringland or rings not properly sealing. Either way it's expensive to fix. Oil consumption issue threads are created regularly on subaru threads. It's a shame since they are so much fun to tune.
 

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Well, OK, I'm an old fart and my sensitivities may be adjusted differently because of that. I'm not morally or ethically crestfallen about my position. There are tons of cars on the road with worse pollution problems than some oil consumption. I'm just commenting on engine wear.

My position is that until an engine is using more than a quart per 1K miles, there's not enough engine wear that you have a mechanical "imperative" to do something about it.

You may be personally concerned - that's a fine ethical position.
You may not pass emissions - OK, then you have a legal imperative to act.

But until you reach the point where you MUST do something, what ARE you going to do?

Is it worth $3,000 or more to you to have an engine rebuilt when all that's wrong is that it's using a quart of oil every 1500 miles? I'll bet it's not. It's darn sure not worth it to me, unless that level of oil consumption results in other problems like a plugged cat or failed emissions test.

I'm not trying to be a pain, I'm just pointing out that cars wear, oil consumption goes up, and there is no hard line where a pointer goes 'sproing" and tells you that you must take action.

And this statement, I just flatly and absolutely disagree with: "...any engine designed in the last 30 years or so that is in good working order should not consume oil, not anything that can be measured with a dipstick anyway."

Tell that to my 1983 280ZX, my daughter's 1991 Camaro RS, my wife's 1994 BMW 325i and my other daughter's 1999 Jeep Cherokee. ALL of them use enough oil that it can be measured with a dipstick. That's what a dipstick is for!
 

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My position is that until an engine is using more than a quart per 1K miles, there's not enough engine wear that you have a mechanical "imperative" to do something about it.!
Agreed, but I still won't say it normal unless the engine has well over 200k miles provided it was properly maintained.

I'm not trying to be a pain, I'm just pointing out that cars wear, oil consumption goes up, and there is no hard line where a pointer goes 'sproing" and tells you that you must take action.!
Depends on why the oil is being consumed. A broken ringland can be a big "sproing".

And this statement, I just flatly and absolutely disagree with: "...any engine designed in the last 30 years or so that is in good working order should not consume oil, not anything that can be measured with a dipstick anyway."!
I understand that there are manufacturer defects and other flukes, but a properly functuioning oil control ring in a properly manitaind engine should be able to do it's job for over 200k miles easily. If it's not something is not quite right. No cause for alarm or even an indicator of furure catistropic failure, but no they would not be working like they should be.

Tell that to my 1983 280ZX, my daughter's 1991 Camaro RS, my wife's 1994 BMW 325i and my other daughter's 1999 Jeep Cherokee. ALL of them use enough oil that it can be measured with a dipstick. That's what a dipstick is for!
How much consumption and how many miles on the engines? You make it sound like consumption is the sole purpose for using the dipstick :D. I've owned eight cars all with over 100k miles to 265k miles and the Subie was the only one that went though oil. They ranged from 81 to 05 foreign and domestic.
 

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I have an 07 Tundra 5.7. I will go 7k-8k miles between oil changes. The oil is always at the same level as it was when I filled it. I use Castrol syntec 5w20.
 

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How much consumption and how many miles on the engines? You make it sound like consumption is the sole purpose for using the dipstick :D. I've owned eight cars all with over 100k miles to 265k miles and the Subie was the only one that went though oil. They ranged from 81 to 05 foreign and domestic.
In each case the car is over 100K miles. The 280ZXT uses a quart around 1200-1800 miles depending on how it's driven....laps on a track definitely use oil faster. Chances are the turbo also contributes, and I know there's some wear in the valve guides and I could use new valve stem seals. The Camaro has around 130K miles on it and uses probably a quart every 1000-1200 miles, but it runs like a watch and I'm not dumb enough to pull the motor and rebuild it when everything works so well. The BMW probably burns a quart around every 3K miles, which is no problem....but it DOES burn oil! There is simply nothing unusual about a vehicle with over 100K miles on it using a bit of oil. If yours doesn't, that's cool and you're fortunate. If it does, there's no need for alarm - just add oil. Engines DO wear - and some use oil when that happens. If you're a used car buyer like I am, there is always some uncertainty about how the vehicle was driven and maintained before you got it, too.

Yes, a broken piston ring of any type is cause for action immediately....BUT - how do you propose to diagnose that? In all the cars I have owned since 1970, I've never had a broken ring in any of them. I know of no diagnostic test that would reveal it, unless you want to pull a plug, insert an illuminated fiber optic device and look for vertical scoring on the side of the cylinder wall. Even then, you won't find a broken ring unless it happens to be jammed in a position where it's scoring the cylinder wall. But it makes no sense to do that if you're just burning a bit of oil.

Of course, if oil consumption becomes "excessive" (a very slippery term as shown by this discussion) then most folks would trade the vehicle rather than yank the motor and rebuild it.

I've run a lot of cars, and I've done a lot of wet/dry compression tests, and I've done my share of complete engine rebuilds....this is not unfamiliar territory. And the primary reasons I use a dipstick for are checking the oil level between oil changes and confirming that the crankcase is full after an oil change. You can also check the oil's color (a horrendously inaccurate way to gauge anything) or look for indications of water in the oil, but that's about it.

I don't see the problem in admitting that cars use oil, and the amount of oil consumption varies. If the car uses a quart every 1500 miles and Person A is upset by that, then rebuild it or trade it. Person B can still be happily motoring along, adding a quart every 4-5 fill-ups, and can do so for a number of years.
 

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You can do a leakdown compression test to test the rings. Smoke when you remove the oil cap is an indicator or a broken ringland too. I fully understand that engins eventually consume oil towards the end of their life cycle, but exsesive consumption is not the norm at 100k mile. Would I have the engine rebuilt? No, but I would start thinking of my next car. Any properly maintained modern engine at the very LEAST should be able to go over 200k.
 

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You can do a leakdown compression test to test the rings. Smoke when you remove the oil cap is an indicator or a broken ringland too. I fully understand that engins eventually consume oil towards the end of their life cycle, but exsesive consumption is not the norm at 100k mile. Would I have the engine rebuilt? No, but I would start thinking of my next car. Any properly maintained modern engine at the very LEAST should be able to go over 200k.
A leakdown test can't discriminate between rings and valves, but at least it's a start. Following with a wet/dry compression test will indeed confirm which is the problem...and agreed, rings are more likely.

I agree that a properly maintained engine can go more than 200K miles....never said that it wouldn't. It just sounds like we differ in terms of the wear indicators we find personally acceptable during that process...particularly the phrase "excessive oil consumption", which we clearly define differently. ;)
 

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OUCH!!! That's nasty!! That could develop into even worse problems! Hope you caught it while the cylinder was still repairable.
 

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I have wondered about this since I bought my 2006 Murano. I bought it in 2009, with only 28,000 miles on it. Now it has over 100,000. It has ALWAYS "used oil". By "used", I mean I don't see any blue or black smoke in the exhaust, I don't see any puddles under the car, and I don't see or small any oil burning anywhere. But once the oil is topped off, I can drive the car for a month or so and it will be at least 1/2 quart down, sometimes up to 1 quart.

This is the first car I have ever owned (previous were 1972 Olds, 1986 Nissan Senta, 200-something Chevy Trailblazer, 1998 Chevy K1500 pickup) that "used" oil like this. I would run these cars anywhere from 3000 to 5000 miles between oil changes and never see any loss on the dip stick.

But this Murano... heck, I just keep Castrol 5w-30 in the garage so I can regularly top up the oil. It's ridiculous. Car runs fine, though.
 

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Good approach. Given the circumstances you describe, the engine is burning it, but not at a rate that's a problem.

I generally don't consider it an urgent situation until the engine burns a quart in less than 1000 miles. At that point it's getting to be a big deal. I'm not sure what your mileage in a month is, but if you're adding a quart a month I don't see any urgent problem. A quart a month is a lot cheaper than an engine rebuild.
 

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My Murano was fairly good on the oil level for the first 150k-ish miles. Then it started sipping oil. I usually did oil changes around 6k miles and a few times I only drained like 3 quarts, oops! Started checking it more often and topping off as needed. The only leaks were around the valve covers, major leaks around 1 coil pack, and the cam sensors, those were all replaced around 250K.

Its at 279K now and I need to add about a quart every thousand miles. The top end has some seepage around the newer seals, but the rear main seal is in rough shape. Not really worth it to drop the powertrain and change the rear main at this point.

As these cars get older and have more miles, all those plastic/rubber seals dry out and wear out. As long as its not pissing oil out, just check it more often, top off as needed, and keep going.
 
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