Well I mixed oils thinking I was making things better. I am dyno testing my engine and after break in which went great, I changed the oil and filter. I used 3 qts Mobil 1 Euro 0W40 and 3 qts Quaker State All Mileage 5W30 with Microguard Select VAFI filter. We noticed the oil pressure would drop a few psi over a certain rpm range, and got worse with higher oil temps. Scratched our heads to figure out why and the only thing we could come up with was the blended oil (and maybe filter). So drained the oil and filled with 6 qts Mobil 1 Euro 0W40 and changed the filter. Problem solved! Pressure now was steadily rising over the run. The attached plot was worst case we saw. The after is also shown and looks like it's supposed to.
Don't mix oils! Oil pressure dropped ---
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The extremes are where one should be most careful with mixing. Severe cold. Extended drain intervals. Exotic engines. And I’d think repeated full out dyno runs would fall into the extreme category.
You don't need to mix oils that's why we pay the price for oil, so it can come all nice and bottled for us as is as intended to be poured into service. No shop or garage is a lab as much as we want it to be. Chemistry cant be altered its a synthetic product physically the two can dwell in the same sump but I always look at mixing oils of different viscosity's even brands with different additive packages like mixing vinegar and oil.
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advlubrication.com is that way -> https://www.advlubrication.com/collections/automotive-lubricants
Personally I'd just get the good stuff and be done with it.
Personally I'd just get the good stuff and be done with it.
OVERKILL
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Yep.
As @Shannow shared years ago, the miscibility standard simply guarantees that oils, when mixed, won't split like mayonnaise, it does NOT guarantee that any performance claims held by the individual products will be retained or that other, unexpected interactions won't occur.
Yep. Certain situations, as outlined above already, are a no-no for mixing oil. I typically don't mix much, except in an old vehicle where I'm just using up some old quarts or something. Fo rmost people, mixing really isn't an issue.
I have 3 vehicles that take 5.2 quarts. That kinda stinks. Remember the 5.25 quart jugs we used to be able to buy? Anyway, I have a 6 pack of Mobil 1 quarts that I use for the ".2" regardless of what the other 5 quarts are. I'm not worried about it.
I have 3 vehicles that take 5.2 quarts. That kinda stinks. Remember the 5.25 quart jugs we used to be able to buy? Anyway, I have a 6 pack of Mobil 1 quarts that I use for the ".2" regardless of what the other 5 quarts are. I'm not worried about it.
I started mixing shortly after joining BITOG. Most of my OC are leftovers topped up with the flavour of the month. Most of the time, my signature will display just the oil that has the greatest concentration. For example, the Honda currently has 1L of 0w-20, and 1L of 5w-30 from the same blender, the rest is CEB 5w-40.
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Join dateThicker oil has higher pressure, don't it? Your previous mix was probably thinner,"at higher temperatures", than the replacement mix of of 0w-40.
OVERKILL
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It would still have a linear track with RPM, just below what one sees with the heavier oil, but that's not what is being observed, we see a dip, which is likely due to foaming/aeration, which could be due to additive package clash, since the mix includes a full-SAPS Euro oil and an API/ILSAC one, which employ very different additive packages.
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SilentType
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What's CEB?I started mixing shortly after joining BITOG. Most of my OC are leftovers topped up with the flavour of the month. Most of the time, my signature will display just the oil that has the greatest concentration. For example, the Honda currently has 1L of 0w-20, and 1L of 5w-30 from the same blender, the rest is CEB 5w-40.
I'm sure you are right. I don't think my 2.5 Camry will rev to 5100 RPMS in Drive.
I've been doing that recently too as opposed to under filling. My Legacy takes 5.2qts and I was usually just putting in 5 but I started topping off with HPL. The 5qts has been Mobil 1 Extended Performance.
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SilentType
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I have 2 quarts of already mixed Supertech full syn high mileage 5W-30, Napa full syn 10w-30, and Quaker State full syn high mileage 10W-30. Would it not be wise to add 2 or 3 quarts Quaker State Euro 5w-40 to this blend? Was thinking of putting it in our Mazda 3.
OVERKILL
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I don't mix oils. At all. So you are asking the wrong guy.
SilentType
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Gotcha. Just wanting to use up that last bit of leftovers. Prolly will just mix it with an equal part kerosene to make a starter to burn brush with.
OVERKILL
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I use leftovers for the mower or pressure washer or something that the sump is small enough that not a lot is needed. If it's a really small amount, I'll use it for a GP lube.
My compressor has Mobil 1 0W-40 in it, my push mower currently has Mobil 1 0W-40 in it and my pressure washer has Redline 5W-30 in it I think? My generator has Pennzoil Ultra Euro 5W-40 in it. The Redline and Pennzoil were both spare quarts I had kicking around, so if you've got OPE, that would be a good use for that 5W-40.
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