Mixing oils of different weights..

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Tzu

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I'm fairly new to this forum, but was wondering if mixing Pennzoil Platinum 5w30 and PP10w30 at a 50/50 ratio yields a true PP 7.5w30 ? My 5.3 liter Silverado is a little noisy on 5w30 and our Impala 3.8 liter specs 10w30 (can use 5w30 if temps are only below 50 degrees). My question is whether they "dissolve" into one weight or do they remain two different grades just mixed together? I know people here mix their own brews with no harm at all, but I was curious on the chemistry behind mixing two different weights. Knowing what little I do, it would seem to me on paper to be a nice ratio for me: a little less slap with the thicker oil for my truck and a bit thinner for the car in winter. Thanks guys.....
 
It does not work that way...


think of oil and water mixing , they have diffrent viscosity. but no matter what you do , they will not mix , you have layer of higher vescosity liquid and lower one. At higher tempreture both will get as close to 30 and "become one" but thats about as close to mixing as you will get.


hope this helps.
 
Originally Posted By: Tzu
I'm fairly new to this forum, but was wondering if mixing Pennzoil Platinum 5w30 and PP10w30 at a 50/50 ratio yields a true PP 7.5w30 ? My 5.3 liter Silverado is a little noisy on 5w30 and our Impala 3.8 liter specs 10w30 (can use 5w30 if temps are only below 50 degrees). My question is whether they "dissolve" into one weight or do they remain two different grades just mixed together? I know people here mix their own brews with no harm at all, but I was curious on the chemistry behind mixing two different weights. Knowing what little I do, it would seem to me on paper to be a nice ratio for me: a little less slap with the thicker oil for my truck and a bit thinner for the car in winter. Thanks guys.....


What do you mean by noisy??
Cold start rattle: 0/30
Hot running rattle 5 or 0/40
Leaks, oil consumption or serious old age: Major brand HM 5w40
Mixing oil is a pointless game for all but serious race or classic car engine owners. Read the owners manual and sell or give away unwanted oil, then buy the right stuff in the right grade.
 
Originally Posted By: Voltmaster
It does not work that way...


think of oil and water mixing , they have diffrent viscosity. but no matter what you do , they will not mix , you have layer of higher vescosity liquid and lower one. At higher tempreture both will get as close to 30 and "become one" but thats about as close to mixing as you will get.
hope this helps.


Not this.

Oils blend fine together. Using the viscosity calculator on PP specs you find that thw 5w30 is 57.5 at 40c and the 10w30 is 63.4 at 40c. Blending the two gives you a viscosity of 60.37 at 40c. You will not find that the two fluids separate or layer in the sump, they are 1 fluid with a slightly different viscosity than either of the originals. The 30 weights on the hot end are virtually identical. I don't see an advantage to the blend, because the oils are so close in specs. I think you could use the 10w30 in both and be fine.
 
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I would use the 5w30 for both engines in the winter, and the 10w30 or some other 5W-40 in the summer, perhaps. I see no real reason to mix the two, nor do I see any way to harm anything either. 5w30 will flow a bit better at first startup when it gets really cold in winter. Like others have said, there is really little difference between these two viscosities of PP. I have used them interchangeably year round. If going into the winter season, and an oil change is due, I put in the 5w30 if I have both on the shelf to choose from.
 
Originally Posted By: beanoil
Originally Posted By: Voltmaster
It does not work that way...


think of oil and water mixing , they have diffrent viscosity. but no matter what you do , they will not mix , you have layer of higher vescosity liquid and lower one. At higher tempreture both will get as close to 30 and "become one" but thats about as close to mixing as you will get.
hope this helps.


Not this.

Oils blend fine together. Using the viscosity calculator on PP specs you find that thw 5w30 is 57.5 at 40c and the 10w30 is 63.4 at 40c. Blending the two gives you a viscosity of 60.37 at 40c. You will not find that the two fluids separate or layer in the sump, they are 1 fluid with a slightly different viscosity than either of the originals. The 30 weights on the hot end are virtually identical. I don't see an advantage to the blend, because the oils are so close in specs. I think you could use the 10w30 in both and be fine.

It's winter so stick to the 5w30 and use the 10/30 in summer. If you must mix oil and not drinks make 110% sure that the oils are exactly the same basic type, regardless of what some experts say you can sometimes get a bad reaction mixing fully synthetic with conventional from a different company. It won't kill the engine, BUT the add packs fight it out and the loser might be the TBN or the Zinc layer.
 
Unless your getting rid of a random quart or two, I don't see any reason to mix. There's no way some guy in a garage can make better oil than a chemist in a lab.
 
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Originally Posted By: whip
Unless your getting rid of a random quart or two, I don't see any reason to mix. There's no way some guy in a garage can make better oil than a chemist in a lab.

This is probably the best quote I have ever seen on bitog. I'm just waiting for the guys to come out of the woodworks now proclaiming how their -5w20 blend of canola oil and Toyota 0w20 has performed flawlessly though.
 
Originally Posted By: Voltmaster
It does not work that way...


think of oil and water mixing , they have diffrent viscosity. but no matter what you do , they will not mix , you have layer of higher vescosity liquid and lower one. At higher tempreture both will get as close to 30 and "become one" but thats about as close to mixing as you will get.


hope this helps.


Why would you post something that you have no knowledge of? You're helping no one with your absolutely 100% incorrect answer.
33.gif
 
Originally Posted By: whip
Unless your getting rid of a random quart or two, I don't see any reason to mix. There's no way some guy in a garage can make better oil than a chemist in a lab.


01.gif
 
Originally Posted By: beanoil
Originally Posted By: Voltmaster
It does not work that way...


think of oil and water mixing , they have diffrent viscosity. but no matter what you do , they will not mix , you have layer of higher vescosity liquid and lower one. At higher tempreture both will get as close to 30 and "become one" but thats about as close to mixing as you will get.
hope this helps.


Not this.

Oils blend fine together. Using the viscosity calculator on Pennzoil Platinum specs you find that thw 5w30 is 57.5 at 40c and the 10w30 is 63.4 at 40c. Blending the two gives you a viscosity of 60.37 at 40c. You will not find that the two fluids separate or layer in the sump, they are 1 fluid with a slightly different viscosity than either of the originals. The 30 weights on the hot end are virtually identical. I don't see an advantage to the blend, because the oils are so close in specs. I think you could use the 10w30 in both and be fine.

beanoil is on the right track. BTW I think those are the Pennzoil Platinum SM spec's you've quoted.

Blending a 5w30 oil with a 10w30 oil will likely produce a lighter 10w30 oil, meaning it will likely no longer pump at -35C. Pennzoil Platinum 10w30 is heavier at all temp's to Pennzoil Platinum 5w30 even at very hot operating temp's. That's because it has a higher HTHS viscosity (3.1cP) and a lower viscosity index (157 vs 177).
A 50/50 blend will give you a light 10w30 with a 167 VI on par with the average synthetic 5w30 at typical operating temp's.

Pennzoil Platinum 5w30 is the lightest OTC 30wt oil generally available in the States so blending with Pennzoil Platinum 10w30 will thicken the oil up a little bit, primarily on start-up. If you can notice the difference then the blend may suit your needs.
 
Originally Posted By: whip
Unless your getting rid of a random quart or two, I don't see any reason to mix. There's no way some guy in a garage can make better oil than a chemist in a lab.


It depends on who that guy is doesn't it? If he's me then certainly not and I'd be willing to guess you'd only do so much better. CATERHAM or Dr. Haas could probably do a lot better.

Without a marketing budget or a wide application range to worry about, do you doubt Widman or Molekule could mix up a better product than the majors at a lower cost?
 
Thankyou for answering my question the way I was trying to ask it. My truck has piston slap and the 5w30 always seemed to make the noise louder and last longer. Maybe others have had different results, but for me I have been using Pennzoil Platinum10w30 ever since. As long as I did not mess anything up by mixing them, I thought a thinner 10w30 would be an ideal blend and then note how the truck responds to it. The Impala is not fussy at all, so this was thought out for the truck use only. Both need changing now, so I have a jug of each and that was the reason to ask you guys first. I don't care if the truck is wearing out faster with thick oil, I just wanted to minimize the noise. I just didn't know how the two would react, if at all. Thanks again.. (Quote)
Oils blend fine together. Using the viscosity calculator on Pennzoil Platinum specs you find that thw 5w30 is 57.5 at 40c and the 10w30 is 63.4 at 40c. Blending the two gives you a viscosity of 60.37 at 40c. You will not find that the two fluids separate or layer in the sump, they are 1 fluid with a slightly different viscosity than either of the originals. The 30 weights on the hot end are virtually identical. I don't see an advantage to the blend, because the oils are so close in specs. I think you could use the 10w30 in both and be fine.
[/quote]
beanoil is on the right track. BTW I think those are the Pennzoil Platinum SM spec's you've quoted.

Blending a 5w30 oil with a 10w30 oil will likely produce a lighter 10w30 oil, meaning it will likely no longer pump at -35C. Pennzoil Platinum 10w30 is heavier at all temp's to Pennzoil Platinum 5w30 even at very hot operating temp's. That's because it has a higher HTHS viscosity (3.1cP) and a lower viscosity index (157 vs 177).
A 50/50 blend will give you a light 10w30 with a 167 VI on par with the average synthetic 5w30 at typical operating temp's.

Pennzoil Platinum 5w30 is the lightest OTC 30wt oil generally available in the States so blending with Pennzoil Platinum 10w30 will thicken the oil up a little bit, primarily on start-up. If you can notice the difference then the blend may suit your needs.
[/quote]
 
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