5W-30 + 10W-30= 7.5W -30?

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If I blend 5W-30 with 10W-30 (50/50)for Spring, summer, and Fall applications, will I get a 7.5W-30? Would this damage my engine? (Mine calls for 10w-30 but I am "swimming" in 5W-30) ($1.28 per quart Mobil 5000, etc) and would like to find a way to make better use of my supply.
 
If your engine calls for 10w-30 it won't hurt one bit to run 5w-30. As long as the first number isn't higher than 10 and the second number is 30 you are fine.
 
THE BASE OILS BEING 5w and 10w would seperate in the oil pan when the engine is not running. The 10w would settle below the 5w so you would have a lighter oil on top of a heavier oil in your engine at start up. Understand?

5w-30
--------------------------------------
10w-30

After start up and the engine has run enough to circulate the oil you would have a mixture of both in the pan.

As the oils now mixed together reach operating temp they would both have the thickness of a 30w at approx 210 F.

When the engine is shut off the 5w and 10w oils will again seperate.

If you are drowning in 5w-30 I would use it instead of going out and buying 10w-30. Unless you are under some type of warranty and need reciepts for oil changes showing you have used 10w-30.
 
lol.gif
What?
 
quote:

Originally posted by Camu Mahubah:
THE BASE OILS BEING 5w and 10w would seperate in the oil pan when the engine is not running. The 10w would settle below the 5w so you would have a lighter oil on top of a heavier oil in your engine at start up. Understand?

5w-30
--------------------------------------
10w-30

After start up and the engine has run enough to circulate the oil you would have a mixture of both in the pan.

As the oils now mixed together reach operating temp they would both have the thickness of a 30w at approx 210 F.

When the engine is shut off the 5w and 10w oils will again seperate.

If you are drowning in 5w-30 I would use it instead of going out and buying 10w-30. Unless you are under some type of warranty and need reciepts for oil changes showing you have used 10w-30.


Ummmmmmm -- respectfully, since when is oil insoluble in oil??? In fact, they will mix immediately and stay very well mixed. Oil bottlers often mix base stocks of differing grades to arrive at a final product of a particular advertised viscosity grade.
 
quote:

Originally posted by serious II:
If I blend 5W-30 with 10W-30 (50/50)for Spring, summer, and Fall applications, will I get a 7.5W-30? Would this damage my engine? (Mine calls for 10w-30 but I am "swimming" in 5W-30) ($1.28 per quart Mobil 5000, etc) and would like to find a way to make better use of my supply.

Such a mix will cause no damage at all, though personally, I'm not a big believer in the concept. Many members here do this, and some have posted very good UOAs on various oddball "soups."

An exception to this, and not a real danger today, would be some early synthetics could cause problems in being mixed. IIRC, there were a few primitive (circa early 1970s, I think) di-ester bases that when mixed with a petro oil would form a substance that amounted to a rubbery sludge. There may have been other troublesome combos, but the products that would cause such problems were far from mainstream (i.e., you'd never have found them at Wal-Mart, Target, or AutoZone), and again, I think most of them are long gone from production.
 
quote:

Originally posted by serious II:
If I blend 5W-30 with 10W-30 (50/50)for Spring, summer, and Fall applications, will I get a 7.5W-30? Would this damage my engine? (Mine calls for 10w-30 but I am "swimming" in 5W-30) ($1.28 per quart Mobil 5000, etc) and would like to find a way to make better use of my supply.

If there was a SA 7.5/30 and both the oils were of same type,MFG and chemisrty then that is about what you would get.,

Differnet vis Base oils, additives are substituted all over the place behind the scene all the time due to cost issues or supply problems.
bruce
 
quote:

Originally posted by ekpolk:

Ummmmmmm -- respectfully, since when is oil insoluble in oil??? In fact, they will mix immediately and stay very well mixed. Oil bottlers often mix base stocks of differing grades to arrive at a final product of a particular advertised viscosity grade.


Soluble, no.
Miscible, yes.
 
they will blend pretty well, and become something between 5w30 and 10w30... the exact low-temp poor/pump point may not be exactly in the middle of the 2 oils- but it will be a little lower than the 10w30 was to begin with...

I'd just recomend using 5w30 winter, and using any stash of 10w30 in the summer... when your 10w30 runs out... just use 5w30 all the time. Even in the summer, the thinner startup viscosity is better for the engine anyways.
 
quote:

Originally posted by Camu Mahubah:
THE BASE OILS BEING 5w and 10w would seperate in the oil pan when the engine is not running. The 10w would settle below the 5w so you would have a lighter oil on top of a heavier oil in your engine at start up. Understand?

5w-30
--------------------------------------
10w-30

After start up and the engine has run enough to circulate the oil you would have a mixture of both in the pan.

As the oils now mixed together reach operating temp they would both have the thickness of a 30w at approx 210 F.

When the engine is shut off the 5w and 10w oils will again seperate.

If you are drowning in 5w-30 I would use it instead of going out and buying 10w-30. Unless you are under some type of warranty and need reciepts for oil changes showing you have used 10w-30.


thats wrong in so many ways..... by your figuring..... i guess what i have been using in one of my old engines out back, 10w-40 havoline and 10w-30 pennz high mileage... it'll blow up?
grin.gif
woooopy
fruit.gif
.....its alright to mix
 
Mixing for finished viscosity, yes. ie: 10w-30 with 10w-40. Mixing for CC performance, ie: 5w-30 with 10w-30, I would not count on it.
 
Like sharks to blood, maggots to rotting flesh, and pirahnnas to meat, BITOGers will quickly pounce on, and dispel, erroneous information.
In other words, the oils would not separate. It would take a chemical genius to separate them, with possibly the help of a centrifuge.
 
quote:

Originally posted by Steve S:
Viscosity clash?

Viscosities won't clash. Vis is just the measurement of the flow resistance (roughly speaking, "thickness") of the oil. Additives might clash in some sense, but IMO, the "soup" UOAs we have here show that in most cases, if the additives are clashing, it's not causing any detectable harm in real world use. Also, mixing within brand should reduce that risk as the add packs within, for example, the M1 line should be similar (within reason, of course).
 
quote:

Originally posted by Pablo:
The REAL problem with posts such as Camu's is that people will read it here, take it as fact, and regurge it later...........oh well, the internet
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!


Yeah, we probably will see that popping up on some of the lesser sites out there. By the way, did you know that you should "NEVER use 5W-30 or 5W-20 oil because it is closer to a grinding compound than a lubricant." --Louis LaPointe
It's true. I saw it on the internet!
lol.gif
 
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