Until recently my only local source for M1 0W40 was AutoZone. But a couple weeks ago while making my rounds through Kmart's Fram-Land I noticed they now have both 0W30 and 0W40! No savings at $4.99, but it was interesting to me they're adding any products. I'd be very surprised if they aren't one of the stores doomed for closure. It's almost deserted most of the time.
Mixing Viscosities.......
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when you do the analysis one will find that you will be closely in the ball park...
also iam talking about using the same brand either all synthetic or all dino
Thanks all and I didn't mean to make something easy more than complex than needed. The answer, from I can discern, is that mixing 2 different weight viscosities with relatively 'small' and 'large' size oil molecules is not the same as starting out with medium size ones. Thus, mixing some 15w-30 Mobil 1 with some 5w-30 Mobil 1 is not the same as if Mobil formulated the 5w-30 to be at the mid 30 wt viscosity range (versus ligher end) to beign with.
As to Mobil 1 0w-40, I can't use it. My car, which is new and under warranty, specs either 5w-30 or 10w-30 so I'll just have to be content with a xxw-30 that is on the thin side of the 30 wt viscosity range or switch to amsoil 5w-30 (I would like this oil more if it had some moly in it) or redline 5w-30 and ignore their non API status...the later 2 oils have a high temp vis of 11.1 and 10.9 against Mobil 1's 9.7/9.8 for their 5w/10w-30.
As most of us tend to do, looking for the ideal oil to use in my application. Thanks again.
As to Mobil 1 0w-40, I can't use it. My car, which is new and under warranty, specs either 5w-30 or 10w-30 so I'll just have to be content with a xxw-30 that is on the thin side of the 30 wt viscosity range or switch to amsoil 5w-30 (I would like this oil more if it had some moly in it) or redline 5w-30 and ignore their non API status...the later 2 oils have a high temp vis of 11.1 and 10.9 against Mobil 1's 9.7/9.8 for their 5w/10w-30.
As most of us tend to do, looking for the ideal oil to use in my application. Thanks again.
I thought one of the major benefits of synthetic over conventional is uniformity of molecule size. So by mixing different weight synthetics, one of the major benefits are diminished.
For those that are mixing 10w30 and 15w50 would be better off getting a 0w40 weight oil without mixing and be done with it in my opinion.
For those that are mixing 10w30 and 15w50 would be better off getting a 0w40 weight oil without mixing and be done with it in my opinion.
I am not sure you can use that comparison. In dyno oil the large long chain molecules tend to sludge or oxidize or shear down, the very light ones will evaporate off. In the case of the two oils 10W-30 and 15W-50 (synthetic) there are none of those very light or heavy molecules. I realize this is an oversimplification as modern oils are more uniform than in the past.
Al, your points well taken. I still imagine uniformity of size plays other roles not mentioned, such as flow, cooling and dynamic lubricating qualities but I could be wrong.
Yes, but the base oil for any given synthetic motor oil is itself a mix of different weight synthetic base oils. Mobil 1 uses two different PAOs, one or more esters, and an alkylated aromatic in its base oil blend. (The ratio of these various fluids is different for each grade, obviously.) So, even with a synthetic, it's not a question of having all the "same size" molecules. What is the big factor is that all the molecules for a given base oil component are ALL the same. This is not true of refined crude, no matter how severely refined. Hydrocracking, hydroisomerization, and hydrofinishing still leave some non-saturated molecules behind.
[ February 04, 2003, 01:00 PM: Message edited by: G-Man II ]
Patman
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Another option is Royal Purple 5w30 for you. It's API certified, and my virgin sample came out at 11.4cst at 100c, so it's a bit thicker 30wt than Mobil 1.
MolaKule
Staff member
There is a method for calculating the mixing of various viscosities, but it requires a programmable calculator and or charts.
The process is described in the Appendix of ASTM D341.
[ February 06, 2003, 10:24 PM: Message edited by: MolaKule ]
The process is described in the Appendix of ASTM D341.
[ February 06, 2003, 10:24 PM: Message edited by: MolaKule ]
This site says that their web calculator will produce results similar to ASTM D341
http://web.sagmilling.com/sagmilling/Sagmilling.nsf/ViscosityPlot!OpenForm
Ken
http://web.sagmilling.com/sagmilling/Sagmilling.nsf/ViscosityPlot!OpenForm
Ken
Patman
Staff member
I just tried it and it didn't work, the graph came up empty. And it didn't ask how much of each different viscosity you were mixing. Does it just assume you mean 50/50?
I'm the webmaster of the sagmilling site. I found your thread while I was checking my web logs today.
I posted a little more information on the site to answer what I think is your question... how do I estimate the visc of a mixture? Assuming that you are entering the visc and temp date for 2 oils (I use 3 points: 0deg, 10deg 100deg) then you visually interpolate between them to get the resultant mixture.
Word of warning, I'm a mining engineer and hydrocarbon processing is a strange world for me. I can't guarantee that the answers are perfect (a hydrocarbon buddy tells me it is close enough for his work though).
Hope this helps. Oh, and you need Java on your browser to see anything... http://java.sun.com/getjava/index.html
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I posted a little more information on the site to answer what I think is your question... how do I estimate the visc of a mixture? Assuming that you are entering the visc and temp date for 2 oils (I use 3 points: 0deg, 10deg 100deg) then you visually interpolate between them to get the resultant mixture.
Word of warning, I'm a mining engineer and hydrocarbon processing is a strange world for me. I can't guarantee that the answers are perfect (a hydrocarbon buddy tells me it is close enough for his work though).
Hope this helps. Oh, and you need Java on your browser to see anything... http://java.sun.com/getjava/index.html
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