"Partial" oil change.

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I think I'd just buy a couple more quarts and use them on the next oil change.

You don't want to waste them but running them for 1,000 miles is wasting them.
If I add the quarts I would extrapolate the time to run it. I.E., if you start with 4 quart capacity and are changing it at 8k miles (2k mi per qt)… you drain & replace 2 full quarts- I would extend the OCI to 12k miles. If you ran 6 quarts 6k miles (1k per qt), I’d extend to 8k miles after replacing 2 quarts. But that’s me.
 
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Ok...how about mixing the Dino with 100% FULL synthetic to achieve a "blend" composition? Is that safe to do?
Yes, of course.

There has been much discussion of the "you're going to get leaks" story on Bob. My take on it is it's probably a myth.

I switch back and forth between dino and synthetic occasionally. I stock up on oil when it's a good buy and use that. At the moment I'm using Syntec "synthetic" in my Accord.

If you do some research on Bob you'll see that "synthetic" oils in North America are really only highly processed dino oil. In Europe "synthetic oil" is oil made from natural gas. But these oils are all compatible and can be mixed without worry.

My only suggestion is that you use oil from the same brand on any given change. Different brands use different additives. They're all compatible but to be completely safe I'd only use oils of the same brand on any particular change.
 
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Personally, I'd keep them. Use them next time you do a engine flush to flush the oil pan.
 
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Who does an engine oil flush? That's right up there with flushing the "bad air" out of your tires with pure nitrogen.

Ummmm....after running a engine flush and draining the oil, I like to run a quart through to flush the oil pan. You'd be surprised what that 1qt can get out after you dump the oil after a flush.

Especially true if you change oil on ramps after a flush and the car/drain plug is not perfectly level/lowest part of pan.
 
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Who does an engine oil flush? That's right up there with flushing the "bad air" out of your tires with pure nitrogen.
Please tell me you know what an engine flush is and you didn't make the correlation you just did. If you did, you'd look like a real clown on a oil board and these guys going to have a fun time kicking your Richard in.
 
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Please tell me you know what an engine flush is and you didn't make the correlation you just did. If you did, you'd look like a real clown on a oil board and these guys going to have a fun time kicking your Richard in.
A forgetful mechanic at a dealership I once worked at forgot to put the oil drain plug in and ran through 4 quarts of oil. The owner was so incensed at the waste of oil he made the mechanic pay for it. According to new wave logic he was really doing an "engine oil flush" and they should have charged extra for it.

I'd be interested in how many guys on "Bob" do an engine oil flush on purpose. I'll bet if anyone does, it's a tiny minority. Most of us know that oil pools in mystery places in an engine block and you can pour all the oil that you want through without flushing it out.
 
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My only suggestion is that you use oil from the same brand on any given change. Different brands use different additives. They're all compatible but to be completely safe I'd only use oils of the same brand on any particular change.
The oil companies use all the same[similar] additive packages . There are only a hand full of additive package formulators on Earth. Look at the posted uoas and voas.
 
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The Earth atmosphere is what % nitrogen?
Exactly. And you would have to do multiple fills with pure Nitrogen to get all that supposed "bad air" out.

As far as I'm concerned unless you plan to set a record on the Salt Lake flats or something like that, you'll be just fine filling your tires with dry air. I reference the ideal gas law in that regard. I consider Nitrogen fills an opportunity to hit up the naive for a little extra cash, or at best a way to not have to buy and maintain an air pump and look all scientific about it. You can call me a Nitrogen tire pressure sceptic.
 
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San Antonio,TX
I have about 2 qt of Super-Tech Dino oil that I'm not inclined to waste. My car calls for 4.3 qt each oil change. Would it be safe to drain out 2 qt of old oil, then replace with new and extended the complete drain and fill interval another ~1,000 miles? I'm just extrapolating logic from a transmission drain and fill, where half the old fluid still remains in the torque converter. I think the oil filter can make it until the complete drain.

Thanks.
Like your atf analogy, yes put the 2 qts in and extend your oci.
 
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There was a study done by Mobil1. They ran motor oil out to 18k miles before changing it. I think that this was before the Extended oils came out for 15k & 20k oil changes; back when 10k was considered pushing the envelope.

The study showed that topping off the oil by as little as a half quart replenished the additives and extended the drain intervals. So, 2 quarts should easily extend your OCI by 1000 miles or more. In addition, changing the oil filter at 8k-10k helped extend the OCI.
 
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