Ford F-150 Truck

[geek2me]

Using a quart of oil per thousand miles may be the "industry standard" but definitely is not normal;

It's not typical for many cars, but it is not "abnormal" and does not indicate any kind of problem.  Does tend to be worse with some brands, might be hard pressed to find a Sub that does not consume close to that.

[jlanciani]

It's not typical for many cars, but it is not "abnormal" and does not indicate any kind of problem.  Does tend to be worse with some brands, might be hard pressed to find a Sub that does not consume close to that.

My 2016 Forester with 25000 miles on it uses about a 1/2 qt. between changes and I'm using 6k mi. change intervals and Mobil 1 0w-20. Using 1qt. per 1,000 miles is rediculous.

[jteneyck]

It's not typical for many cars, but it is not "abnormal" and does not indicate any kind of problem.  Does tend to be worse with some brands, might be hard pressed to find a Sub that does not consume close to that.

We'll agree to disagree on this one.  

Just to be clear, my last two Subaru's have used no oil between changes at 3K miles.  None.

John

[daddo]

It isn't so much that the oil gets dirty- it's that it starts to break down and thus loses it's ability to properly lubricate. The small particles in the oil over a certain micron in size can be damaging. Most black carbon is too small to worry about.
With a good synthetic oil and a good filter system, you could almost go on perpetually. Some have done it and are doing it by just changing the filters and adding oil as it needs it.
Not something I would do- but it is being done and to the tune of 200k- 400k miles by some brave souls.

I disagree about the Amsoil transmission fluid. It has out performed all the others I have used- including Mobile1 ATF.
The Amsoil motor oil..?...I won't put that junk in my vehicles!

[geek2me]

It isn't so much that the oil gets dirty- it's that it starts to break down and thus loses it's ability to properly lubricate.

Maybe we are debating semantics, depending on what you mean by "break down".  People commonly use that terminology to refer to thermal degradation of the base stock, but that won't happen at any temperature likely to be experienced in a motor vehicle.  It's mostly the "dirt" in the oil that controls oil change interval, wear effects on the oil and additives are an order of magnitude beyond the OCI.

Machinery Lubrication had a good article that explains "oil breakdown" and what to watch for in the oil analysis.  Not too technical and worth a read. It's available online: http://www.machinerylubrication.com/Read...-breakdown

[Snipe Hunter]

It is my understanding that car dealers these days.. make very little of their total profit from new car sales.  A large chunk of the dealer income is parts and service plus performing warranty work.  We haven't had maintenance, other than warranty work, done at the dealerships, in a long time.

We have the work done at our local care care center, where we have done business for more than twenty years.  I can trust the owner, they are twenty to thirty percent cheaper, and stand behind the work.

100% correct. Services and additives are the most profitable pieces of the service department because they have almost no overhead. The Tech and service writers get paid a commission by the additive distributor when they sell it.

[Snipe Hunter]

Sorry to go off on a slight tangent, but wanted to comment about Mobil 1.  On my first Subaru I changed the factory oil to Mobile 1 at 1000 miles, and personally changed it and the filter every 7500 miles.  Immediately, the car started to use a quart of oil between changes.  I asked Subaru about it and they said it wasn't unusual.  Really?  My wife's BMW never, ever used a drop of (synthetic) oil. 

A couple things. A Suburu and a BMW aren't the same thing so they will not have the same issues. I believe BMW recommends synthetic from day one. I don't think Subaru does.
Another thing. It's probably not a good idea to start running Mobile 1 before the motor is broken in on the Subaru. 1000 miles is not broken in. I've always been told not to switch to synthetic until the 1st or 2nd scheduled oil change. Certainly not before the motor has had time to break in.

[jteneyck]

A couple things. A Suburu and a BMW aren't the same thing so they will not have the same issues. I believe BMW recommends synthetic from day one. I don't think Subaru does.
Another thing. It's probably not a good idea to start running Mobile 1 before the motor is broken in on the Subaru. 1000 miles is not broken in. I've always been told not to switch to synthetic until the 1st or 2nd scheduled oil change. Certainly not before the motor has had time to break in.

I think you are right.  But as I think back on the it now, I'm sure I didn't change the oil until the first recommended oil change interval at 3000 miles, or whatever it is, not at 1000 miles as I said before.   That probably still wasn't enough to completely break in the engine, however.  I remember a guy who used to race cars saying that the engines on some cars never get really broken in; they are just driven too gently.  I certainly drove that first Subaru hard, it was a WRX, but maybe not for long enough before going to synthetic. 

This will all be a non-issue soon.  I'm sticking with regular oil on this car.  The next one will require synthetic from day one. 

John

[GHR]

[quote pid='7397700' dateline='1480729102']
It's mostly the "dirt" in the oil that controls oil change interval, wear effects on the oil and additives are an order of magnitude beyond the OCI.
[/quote]

I use oil filters and synthetic oils that are rated for 15K mile. The filter may not last 15K miles. But (in theory) one can always change just the filter.

[geek2me]

I use oil filters and synthetic oils that are rated for 15K mile.

Not sure who you mean is "rating" the filters and oil, but it sounds like you mean the oil and filter vendors.  Exceeding the vehicle manufacturer's recommended change interval is likely to void your warranty if you have issues they can claim are oil related.

Some conventional oil manufacturers do provide high mileage warranties on vehicles when their oils are used and their recommendations are followed. A lot of requirements and "jumping through hoops", but if you keep the records and proof it seems to offer reasonable coverage.