Help me "over think" this as many of us here like to do - Mixing 0W-20 with 15W-50 to achieve close to 5W-30

[Slick]

Background: Had Son in Law give me (4) 5 Quart Jugs of Quaker State Synthetic 0W-20 ILSAC GF5/Dexos1 oil. Not sure why he even purchased them as he was a Quick Oil Change groupie. He has had the oil for about two years so not it would not be fair to the next purchaser to return the oil. Now that he is "letting me" (= free oil changes for him) change his oil with my filters and oil supply he has no use for the oil.

Since I am tend to be a moderate "viscosity thickie" and after reviewing the owners manual for his 2020 Hyundai Ionic Hybrid oil specification it also shows 5W-30 as acceptable to the 0W-20 printed on the oil fill cap. Plus the last two oil service changes (at 138,000 and 144,000 miles) I have used 05W-30. (My humble opinion the idle valve train noise is a slight bit quieter)

So the exercise

Not wanting to waste the 0W-20 and having a supply of 15W-50 Mobil One I no longer use much I would like to mix the two different viscosities for the future oil changes in the Ionic.
Goal is to get as close to 5W-30 as I can can and use up both oils.

Any concerns this group see other than I am "overthinking" this and should just use the 0W-20 as is.

Is there a proven way the oil blenders would use to find the closest mix ratio to achieve a 5W-30? It is surely not worth sending the mix for oil analysis as the cost would exceed the benefit.


Thanks

Slick

 

[Jetronic]

There's no way of knowing what winter grade you will end up with. If the weather is such that you can't use a 10W-xx or above, I would not mix them. It's not impossible that you end up with a 15W-30.

the KV100 can be brought into the xxW-30 range no problem.

 

[twX]

Is there a proven way the oil blenders would use to find the closest mix ratio to achieve a 5W-30? It is surely not worth sending the mix for oil analysis as the cost would exceed the benefit.

Use this viscosity mixing calculator from Widman. It's designed for kinematic viscosity, but should work well enough for HTHS.

If the oils being mixed have an HTHS of 2.6 and 4.5 cP, a 75/25 mixture will get you the HTHS of a 5W-30, at around 3.0 cP.

As for the W rating, I don't know if it's possible to predict, and you may end up with something thicker than 5W. I'd just use pure 0W-20 for winter.

 

[JAG]

The different base oils and possibly the different VII types in the mixture can cause unpredictable deviations from calculations that assume no weird interactions. Your two oils’ base oils are similar in solubility, so the risk is minimized. I doubt weirdness will be significant in warmer months. If it will be in use during bitter cold weather, error on the side of caution with the percentage of thick oil.

I currently have similar blasphemy in my engine: 3.6 qts. of Amsoil SS 5W-20 and roughly 1/3 qt of Amsoil V-Twin 20W-50. Purpose was to use up the 5W-20 but have slightly more viscosity. It’s not ideal but it had a one-time purpose.

 

[ecotourist]

When our daughter's ancient Toyota Corolla was near the end of its life, I drained the oil and put in a bit of this and a bit of that to make 4 liters of "motor oil". But I wouldn't do that on a car that was particular about oil or that had a lot of life left.

That was about the last change I ever did on that Corolla as we replaced it with our Solara V6 shortly afterwards.

I recently changed the oil on my Accord and used Syntec 5W-20 (the remains of a past change) topped up with Syntec 0W-20. Oh the horror!

 

[gfh77665]

There have been countless "frankenblends" concocted and used here through the years. I don't remember a single one having an issue. Every quality oil will state their oil is fully compatible with other quality oils.

You can rest easy, the viscosity will fall somewhere in between, and 5w-30 is likely the closest mark. If you really want to split hairs, use 3qt. of the 0-20 and 2qts 15-50 in the winter and then reverse it, use 3qt 15-50 and 2qt 0-20 in the summer. Personally I would mix it 50-50 and never give it another thought. Engines are WAY more tolerant of viscosities than people think. A vehicle starts and goes from ice cold to very hot in minutes, and oil is along for the whole ride.

 

[ka9mnx]

Not a back yard garage tribologist and don't pretend to be one.

 

[alcyon]

Mix only when you want use up old stocks. Run a few oci. After you used up remaining stocks go with one fill.

 

[KCJeep]

I would not be changing oil in someone else’s Hyundai if I were you. When that engine grenades (there’s a high possibility it will) your son in law may blame you. Also would not want to be trying to get Hyundai to make good on the warranty with your frankenbrew mix in the maintenance history.

JMO.

 

[Hohn]

You aren't going to hurt anything mixing, nor are you going to produce anything better than what's already bottled.

I don't oppose mixing if it's just to use up leftovers on a shorter OCI. It's those who think they are secretly concocting a super oil to overcome the Big Oil Conspiracy that makes me look askance.

 

[webfors]

As mentioned, you can't predict the winter rating... so if this is summer months go for it.

 

[Slick]

Use this viscosity mixing calculator from Widman. It's designed for kinematic viscosity, but should work well enough for HTHS.

If the oils being mixed have an HTHS of 2.6 and 4.5 cP, a 75/25 mixture will get you the HTHS of a 5W-30, at around 3.0 cP.

As for the W rating, I don't know if it's possible to predict, and you may end up with something thicker than 5W. I'd just use pure 0W-20 for winter.

twX

Appreciate the viscosity mixing calculator.

Good idea to just use the straight 0W-20 in the midwest winter and use the mixed blend for summer time.

Best regards

Slick

 

[Hohn]

twX

Appreciate the viscosity mixing calculator.

Good idea to just use the straight 0W-20 in the midwest winter and use the mixed blend for summer time.

Best regards

Slick

I recommend 0w30 for midwest winters because all those cold starts and cold idles make for lots of fuel dilution.

 

[Slick]

The different base oils and possibly the different VII types in the mixture can cause unpredictable deviations from calculations that assume no weird interactions. Your two oils’ base oils are similar in solubility, so the risk is minimized. I doubt weirdness will be significant in warmer months. If it will be in use during bitter cold weather, error on the side of caution with the percentage of thick oil.

I currently have similar blasphemy in my engine: 3.6 qts. of Amsoil SS 5W-20 and roughly 1/3 qt of Amsoil V-Twin 20W-50. Purpose was to use up the 5W-20 but have slightly more viscosity. It’s not ideal but it had a one-time purpose.

JAG

Great input. I will even be conservative and use the straight 0W-20 in our Midwest winter.

I to also have some V-Twin 20W-50 that I used to use in my 2003 Buell XB9S until I switched it over to HDEO 15W-40 API CK-4 that I use in my diesel tractor and generator.

Reference the 5W-20 grade. My son has a 2014 2.5L Malibu that calls for 5W-20 (GM now suggests to replace 5W-20 with the newer 0W-20). The Malibu has been doing fine years on 5W-30.

Thanks

Slick

 

[Slick]

There have been countless "frankenblends" concocted and used here through the years. I don't remember a single one having an issue. Every quality oil will state their oil is fully compatible with other quality oils.

You can rest easy, the viscosity will fall somewhere in between, and 5w-30 is likely the closest mark. If you really want to split hairs, use 3qt. of the 0-20 and 2qts 15-50 in the winter and then reverse it, use 3qt 15-50 and 2qt 0-20 in the summer. Personally I would mix it 50-50 and never give it another thought. Engines are WAY more tolerant of viscosities than people think. A vehicle starts and goes from ice cold to very hot in minutes, and oil is along for the whole ride.

View attachment 278049

gfh77665

Thanks for the input and great chart (I even had to look for my dollar store reading glasses - sad what maturity brings)

I agree engines are more tolerant on viscosity than many think. I often think that many of us (me included) fuss more on our engines that we do on our personal health.

Best regards

Slick

 

[Slick]

You aren't going to hurt anything mixing, nor are you going to produce anything better than what's already bottled.

I don't oppose mixing if it's just to use up leftovers on a shorter OCI. It's those who think they are secretly concocting a super oil to overcome the Big Oil Conspiracy that makes me look askance.

Hohn

For me it is not making a super oil blend but just using up the available oil on a well used 144,000 mile daily driver.

Thanks

Slick

 

[Slick]

I would not be changing oil in someone else’s Hyundai if I were you. When that engine grenades (there’s a high possibility it will) your son in law may blame you. Also would not want to be trying to get Hyundai to make good on the warranty with your frankenbrew mix in the maintenance history.

JMO.

KCJeep

I recently did the 144K miles oil/filter change and the Hyundai will first get my "use the oil up blend" at next oil/filter service at 150K. As twX suggested earlier to use the 0W-20 in winter and save the "mixed Blend" for summer. Good Idea that I will follow.

This vehicle is well past the 100K Hyundai Engine warranty. I told him he is likely past the "statistical" engine life for this vehicle. I would like to see if we can get well past 200K without any engine work.

Thanks

Slick

 

[BrendanC]

my two cents is; do not mix oils, especially those from different manufacturers.

 

[JimPghPA]

First, never mix different brands of oil. There are 4 companies that make the additives, and different oil companies may be using different additive packages in the oil, and some additive packages don't work well together.

Second, the oil molecules will still change from a liquid to a wax at the same temperature they did before mixing with other oils. You will end up with something similar to a convince store slushie. If there is enough of the oil that does not phase change to wax, it will still flow. If not enough it will not flow well enough when cold.