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Question: Using "used" oil for top up oil?
- Thread starter blupupher
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I gave a neighbor waste oil years ago to use in an oil burning Chevy van. The oil was coming out of my fairly new van at the time running short OCI's. It saved him money and was a form of recycling oil. I guess if you have fairly new well maintained vehicle in your fleet and an oil burning beater it would save some money and recycle oil.
Why would anyone gently use oil?
Oil has a job. Leave it in there until its done, drain and send it off to be recycled.
I don't care how old the engine is, if I am changing the oil, it gets new stuff, otherwise just leave it in there and keep adding until the engine dies.
Use new Mobil 1 EP and top off every 1500 miles. Use a quality filter and change it every 15,000 miles. Every 60,000 miles or so do a complete change to flush out the pan.
Just dumped my 1 yr old 5w-30 Mobil 1 with 980 miles on it and took it to the recycling center yesterday. Replaced it with another year's worth of M1 at $2/qt. If someone had wanted that recycled oil I'd have been happy to give it to them.
In an oil burner I would run thicker viscosity than originally specified.
Originally Posted By: Smokescreen
Why would anyone gently use oil?
Oil has a job. Leave it in there until its done, drain and send it off to be recycled.
I don't care how old the engine is, if I am changing the oil, it gets new stuff, otherwise just leave it in there and keep adding until the engine dies.
Originally Posted By: Gene K
Use new Mobil 1 EP and top off every 1500 miles. Use a quality filter and change it every 15,000 miles. Every 60,000 miles or so do a complete change to flush out the pan.
Without a UOA, you really don't know how much life is left in the oil from the Toy when you drain it, but a UOA would kill the economics of your idea.
I personally wouldn't bother.
Too many unknown unknowns to risk an engine still in its prime, even though the risk is small.
You can pick oil up quite cheaply.
I bought a case of RK HD30 to use for top-ups and the OPEs for $1.29/qt, for example.
I've recently paid even less for PP after MIR and not a whole lot more for M1 and D1 after MIR.
What I'm trying to put across is that the risks, while low, are real and the savings aren't all that great.
The inconvenience alone seems to me to negate the savings.
Originally Posted By: Mark_Walk
Originally Posted By: Gene K
Use new Mobil 1 EP and top off every 1500 miles. Use a quality filter and change it every 15,000 miles. Every 60,000 miles or so do a complete change to flush out the pan.
I'm thinking of leaving some used oil in the sump at OCIs as it's already got some reacted AW additives.
But adding used oil at the end of an OCI doesn't really make sense unless it's a beater. I agree that any oil is better than none, but would rather finish a quart down than add some used oil at the end.
I like the idea of using a simple HD30 with simple add pack as top off.
edit, still trying to find the old thread where I recommended this as a top off
http://www.penriteoil.com.au/products.php?id_categ=10&=&id_products=357
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Does permanent shear affect HTHS?
If so, topping off an XW-20 with SAE30 or XW-30 with SAE30 or SAE40 makes sense.
Using the next thicker multi-grade instead of a straight weight, would be like Forrest said,
a box of chocolates; you never know what your gonna get.
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Yep, permanent shear affects HTHS...half the percentage KV100 loss up to about 15% loss of KV100, then it flattens out.
That was my original gidea with an SAE30 top off.
3.5HTHS would bolster an XW30 that was shearing or fuel diluted, and would have little impact on an XW40, maybe restore it a tad.
The reason I put that question up is because Jetronic corrected me in stating that published HTHS figures include temporary viscosity loss due to the action of VMs.
The thread was about straight grade oils, which are just as likely to thicken as thin as they age, and do not display temporary high shear loss.
For example, if we took an old school 10W40 engine oil with a published HTHS of 3.9 then tested it at drain time, what could we expect?
We could perform this experiment 1st with sonic shearing that would eliminate the variables, then a new batch in the engine.
If we are experimenting with low viscosity engine oils, lets see how thin we can go, knowing the post sonic shear HTHS might save an engine or two.
Stating the obvious, you have many miles left in the used oil. 3K and 5K changes on modern oils from engines w/o mechanical failures and no carbs, is a gimme 
You are part way to another oil change when you add your first qt. You are most of the way to a change when you add the second qt. It's all used oil by the time you add. What's the big deal ...
I'd do it in heart beat if I was sure my oil was in a clean container. I wouldn't even care about mixing the two used oils as long as the containers are c,lean.
As the others have said, if you are going to buy oil, I'd buy an SAE 30 HD and use that. But as long as you have good used oil, I would not bbuy anything
Mine is not, it's in a used oil (all types) mixed conatiner collected for the recycle oil bin in town.
You are part way to another oil change when you add your first qt. You are most of the way to a change when you add the second qt. It's all used oil by the time you add. What's the big deal ...
I'd do it in heart beat if I was sure my oil was in a clean container. I wouldn't even care about mixing the two used oils as long as the containers are c,lean.
As the others have said, if you are going to buy oil, I'd buy an SAE 30 HD and use that. But as long as you have good used oil, I would not bbuy anything
Mine is not, it's in a used oil (all types) mixed conatiner collected for the recycle oil bin in town.
So just reviving this to update.
I just changed the oil in the truck today. Original fill was Valvoline Next gen 5w-20 (3 qts) and Pennzoil Platinum 5w-20 (3 qts) with a Carquest filter.
I went to 3,400 miles this time before I changed it, not because of miles, but it had been over 7 months since the last change.
With the short tripping I do, that was longer than I wanted it in there.
I was planning to go to 4,500 miles, but I am just not driving far enough.
Late last year, I drained the oil from the Scion into an empty, clean Valvoline Nextgen bottle. Just under 5000 miles on the oil.
I got about 3.5 qts of usable oil from that (some left in the filter, a little drained before and after).
I did use 1.5 qts of the PP² (my nickname for Pennzoil Platinum on its second use) during the oil change.
I added 1/2 qt at 1100 miles in, then another qt @ 2,400 miles. It was getting close needing to add another qt so I could try for 4500 miles, but just could not make myself wait, at the rate I drive now it will be another 2 months.
Sure I should do a UOA on this to see how it did, but I am not that interested in how it does, just so long a it does something, which it seems to be doing.
PP² may not be for everyone, but for me I think this will work for my current needs for a while. I still have 2 qts of PP² in my stash for this OCI, and will have another oil change due on the Scion before I use all of that (although the Scion currently had some Auto Zone 0w-20 syn in it right now).
In a beater yes, in one of my better rides, no.
i use old oil. I've got an 07 RAV4 with the 2.4 2AZ-FE at 70k miles. it's burning about .5 quarts of oil per 1000 miles. my oci is 4k miles and i use that old oil as top off oil. i tried marvel mystery oil the last oci and didn't notice a change in oil consumption.
When you are reusing used oil you are really economizing so I' m kind of baffled on the logic here. If the used oil has a high enough TBN to reuse why bother to use new oil at all? Do a severe schedule with the used oil.
If I lived in the heat of Texas with an oil burner I would use a 10w-30 or thicker (high mileage oil preferred) and attempt to source the cheapest conventional oil.
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