What causes oil consumsion between oil changes. My Subaru is sitting on about 5500 miles and 8 months since last oil change. It has consumed about .25 qt (still in the good zone). I hear of people consuming about 1 qt on extended oil changes. I do mixed driving and current fill is PU 10w30.
What causes oil use between oil changes?
- Thread starter stygz
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I think we see a bit more now because most engines now have twice as many valve guides as they used to.
Engine, wear, bad valve seals, valve guides, rings, oil too thin, or breaking down, or just normal use. Pick one it happens. What sucks is normal use can be as much as a qt of oil per 1000 miles, and in some cases more, and that's for new cars. Your Subaru is doing just fine.
In nearly 10K the CRV uses .25 of a qrt....a concern no. There are so many factors that can contribute to consumption.
A lot of Subaru drivers would love to have that little consumption. I run Pennzoil High Mileage 5W-30 for 5-6k intervals in a 2000 2.5RS and do not add any oil between changes. A lot of the Subaru forums where 0W-20 is specced (BRZ, new Forester, etc.) have ongoing oil consumption threads.
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-Dennis
ALL piston engines consume at least a small amount of oil. There's no such thing as an engine that "doesn't use any oil." The engine sprays oil on the cylinder walls when the piston is at the top of its stroke to lubricate the rings and piston skirt. When the piston comes back down, the oil control rings scrape a controlled amount of oil off, leaving a very thin film to lubricat the upper compression rings. Part of that thin film gets burned away when the cylinder fires. Nature of the beast.
In a very healthy, tightly-built, mildly tuned engine, that consumption will amount to well under a quart in 6000 miles- my 150,000 mile Cherokee, for example, never needs a quart between 6000 mile changes, and is only down about a cup.
Engines with more piston ring length- big-bore v8s for example- tend to burn more. Little 4-poppers burn much less, all other things being equal.
Some engines are also naturally "looser" than others and can burn a more oil past the rings- high-performance engines for example. Wear will eventually cause a drastic increase in consumption past the rings, as can using the wrong grade of oil. Too thick can cause more consumption past the rings as easily as too thin. When the oil is too thick, the oil control ring can't "scrape" it all away leaving a thicker layer to get burned off.
Another source of consumption already mentioned is the valve guides- like rings, they need to be supplied with oil and at least a tiny part of that oil gets lost when the valve is open and the intake charge washes it off the valve stem or the exhaust gasses burn it off. When the guides wear or their umbrella seals break down, consumption goes up.
Finally, one of the biggest source of consumption can be the PCV system. If there's not a good system to separate oil mist from blow-by vapor, then that mist gets sucked into the intake and burned.
In a very healthy, tightly-built, mildly tuned engine, that consumption will amount to well under a quart in 6000 miles- my 150,000 mile Cherokee, for example, never needs a quart between 6000 mile changes, and is only down about a cup.
Engines with more piston ring length- big-bore v8s for example- tend to burn more. Little 4-poppers burn much less, all other things being equal.
Some engines are also naturally "looser" than others and can burn a more oil past the rings- high-performance engines for example. Wear will eventually cause a drastic increase in consumption past the rings, as can using the wrong grade of oil. Too thick can cause more consumption past the rings as easily as too thin. When the oil is too thick, the oil control ring can't "scrape" it all away leaving a thicker layer to get burned off.
Another source of consumption already mentioned is the valve guides- like rings, they need to be supplied with oil and at least a tiny part of that oil gets lost when the valve is open and the intake charge washes it off the valve stem or the exhaust gasses burn it off. When the guides wear or their umbrella seals break down, consumption goes up.
Finally, one of the biggest source of consumption can be the PCV system. If there's not a good system to separate oil mist from blow-by vapor, then that mist gets sucked into the intake and burned.
I have to laugh when I some of these posts about oil use like a quart in 2000 miles.
I had a 33 Ford that I could run wide open to the next town and back and when I got back from this 14 mile run I would add 2 quarts, then check to see how much more it needed.
The poor old V8 was just a little worn.
You could see the top ring between the piston and cylinder wall there was so much wear when I pulled a head.
The surprising thing is it had enough compression to start!
I had a 33 Ford that I could run wide open to the next town and back and when I got back from this 14 mile run I would add 2 quarts, then check to see how much more it needed.
The poor old V8 was just a little worn.
You could see the top ring between the piston and cylinder wall there was so much wear when I pulled a head.
The surprising thing is it had enough compression to start!
I do 5000 mile changes on all of my cars. I don't get any noticeable consumption because obviously the engine tolerances are still fine. Extended oil changes allow enough friction due to additive depletion to reduce tolerances which over time causes consumption. So pay me now or pay me later.
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My 1998 Corvette with 140,000 miles uses 1/4 to 1/2 quart of oil in 6500 mile oil changes.
GM considers 1 quart in 800 miles to be acceptable oil usage and replaced some rings in Corvette's (there was a problem when they changed from selective assembly to just using tolerances of rings and pistons) with higher usage. That's 8.125 quarts in 6500 miles, NOT what I would consider acceptable !
GM considers 1 quart in 800 miles to be acceptable oil usage and replaced some rings in Corvette's (there was a problem when they changed from selective assembly to just using tolerances of rings and pistons) with higher usage. That's 8.125 quarts in 6500 miles, NOT what I would consider acceptable !
Subaru has recomended 7500 mi oci using a synthetic oil under normal conditions. I have been using a syn oil since I got the vehicle with 30k on it. This will be the first time I will go the full 7500 oci. I plan on sending in a sample to blackstone labs to verify it is working for me. I dont intend on going any longer than that since it will take me about 10 months to do this (assuming no road trips taken).
Originally Posted By: ARB1977
In nearly 10K the CRV uses .25 of a qrt....a concern no. There are so many factors that can contribute to consumption.
Is 10k oci going my the oil life monitor/maint reminder? I am concidering a new CRV for the next vehicle.
In nearly 10K the CRV uses .25 of a qrt....a concern no. There are so many factors that can contribute to consumption.
Is 10k oci going my the oil life monitor/maint reminder? I am concidering a new CRV for the next vehicle.
I dont have any concerns about what little my tribeca (3.0 flat 6) is consuming. After checking it last night I saw the level had moved on the dip stick and it was the longest I have ever went on an oci. But good to know It sounds like it is doing better than most subaru's
None of my vehicles engines use any noticalbe oil between the ~5K mile OCI's. That's not to say that the engines wouldn't use any oil if gone longer OCI's.
Years ago, every engine I owned, used oil between OCI's(3K mile), some more than others. And these were all 2 valve per cylinder engines not, the 4 valve per cylinder that we have now(3 vehicles). It was always wise to check the oil level druing fueling until we learned the engines oil useage.
Years ago, every engine I owned, used oil between OCI's(3K mile), some more than others. And these were all 2 valve per cylinder engines not, the 4 valve per cylinder that we have now(3 vehicles). It was always wise to check the oil level druing fueling until we learned the engines oil useage.
Our Prius uses about 1/4 quart every 3k. Our Hyundai uses maybe 1/8 quart in that many miles.
The Prius is newer. What gives?
The Prius is newer. What gives?
ZeroSoma, my 2007 Toyota Yaris (1.5 liter) never needs a top-off of the oil between 6,500 mile OCI's. Even at 145,000 miles. I wonder if your Prius engine has a defect.
The Hyundai must be a better car.....
Actually, your Prius has nearly twice as many miles on it which is probably a factor.
Actually, your Prius has nearly twice as many miles on it which is probably a factor.
I must be the lucky one. On one of my vehicles (only just this one) a VW, I have owned since new in 99 and still have it kicking around - and not once has I had to even top a drop off in this car. It called in the book for 10k miles OCI after the first one or two being done at 5000 miles, but I never paid attention to that and did normally change oil at about 6k each time around and a few higher in the 7k plus range and one I pushed to 9k. Anyway, like I said...never used a drop still till this day...but I do know most cars will use a little as my other cars do from time to time.
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