# Mobil 1 5W-30 vs 0W-30 AFE

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#### ZraHamilton

I am trying to determine which is better for cold winter start-ups. The viscosity of the 5W-30 is actually 1 cSt thinner at 40C. Mobil 1 5W-30 - @40C - 61.7 cSt Mobil 1 AFE 0W-30 - @40C - 62.9 cSt However, that is at 104F, and I would like to know how they compare at around 32F (0C). Thanks to anyone who can help.

At 0C, there's literally absolutely nothing between those two oils.

Would there be any difference at -18C?

If your car recommends 5w30, I would just use the 0w30. Even if barely a difference between the two. Same price for the oil, and my experience has been that AFE always runs smoothly in my car. Either will work but I like to think the 0w will be easier on my engine during any cold starts. Even if no difference, what have i lost in ability vs using 5w30?

Thanks for the advice Rolla07. Most of my driving is 10 minute trips, so I want an oil that will heat up as quickly as possible.

I like 0Ws not only for cold starts but also the higher viscosity index.

Agreed. I've also heard that Mobil 1's AFE oils have a high percentage of PAOs in them. This means that it could be achieving the higher viscosity index with little to no viscosity index improvers.

Here are is the definition under ASTM D5293 for cold cranking. Cold Crank Viscosity ASTM D5293- Test Method for Apparent Viscosity of Engine Oils Between -5 and -35 C Using the Cold Crank Simulator This test method covers the laboratory determination of apparent viscosity of engine oils at temperatures between –5 and -35C and at high shear rates. The results are related to engine cranking characteristics of engine oil. A measured amount of sample is subjected to an extreme low temperature for 3 minutes. The rotor spins for 1 minute in the sample and the speed of the rotor is measured by keeping ohms resistance at zero. The speed-reading is used to determine the viscosity on a calibration curve. The cold cranking simulator (CCS), ASTM D5293, correlates with engine cranking speed at low temperatures. Cold cranking viscosity simulates the viscosity of an oil in crankshaft bearings during cold temperature start up. Cold cranking viscosity limits, determined by the CCS, are defined in the SAE J300 Standard, as shown below: Cold Crank Viscosity Low temperature viscosity (mPa s) Max (CCS) Temps are degrees C. 0W 6200 @ -35 5W 6600 @ -30 10W 7000 @ -25 15W 7000 @ -20 20W 9500 @ -15 25W 13000 @ -10

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Originally Posted By: ZraHamilton
I am trying to determine which is better for cold winter start-ups. The viscosity of the 5W-30 is actually 1 cSt thinner at 40C. Mobil 1 5W-30 - @40C - 61.7 cSt Mobil 1 AFE 0W-30 - @40C - 62.9 cSt However, that is at 104F, and I would like to know how they compare at around 32F (0C). Thanks to anyone who can help.
At -40 F/C, the results are fairly dramatic and you can make yourself a You Tube video to show everyone. At higher temps the difference is less dramatic. 0W-30 at -35 C flows like 5W-30 at -30 C which flows like 10W-30 at -25 C. I've personally done flow tests at -20 C and I can say you'll notice the difference between 5W-30 and 10W-30, but it is not dramatic like at -40. And yes, you probably wouldn't notice a difference between 0W-30 and 5W-30 at 0 degrees C. SF

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The difference between the two of those oils are negligible at 32F. The 0w30 would pay dividends at roughly -20F which you would hardly ever see in Tennessee. JMO. Good luck.

Originally Posted By: Rolla07
Either will work but I like to think the 0w will be easier on my engine during any cold starts.
see, that's the problem with the laws of physics...they don't really mind what people like to think. at 32F, if anything has a slight edge it will be the marginally thinner 5W30. As to what you've lost Dexos HTO-06 lighter basestocks with more "fillers'

The oil viscosity choice will not matter as far as cold starting until you start to ge below -25 *f.

Originally Posted By: Astro_Guy
That's not accurate below 0C. Viscosity measured via CCS and MRV roughly halves as you increase temperature by 5C. So a 0w-30 with a CCS of 5,600cP @ -35C would be roughly 2,800cP @ -30C. However, the issue is that if you are comparing say a 5w-30 and a 0w-30, at somewhere around -15C, that trick stops working and we start heading toward what you'd see in the calculator. Basically, that's where an oil's VI starts to become relevant. It's not a hard line, as it would vary based on base oil, PPD's, VII treatment....etc but it seems to be somewhere in that neighbourhood. So we have this range between -15C and 0C where the visc calc isn't accurate and the halving rule isn't either.

Originally Posted By: Bxnanaz
I like 0Ws not only for cold starts but also the higher viscosity index.
Higher Vi in a finished oil is usually due to more viscosity improvers used. Although I like the 0w- oils myself 1 oil from -35*f to over 100*f.

I use 0w30 on mine. I have run 0w40. My car recommends 5w30. There was no difference other than 0w have more PAO content which makes me last up to 5k OCIs

I probably would have run M1 0W30 AFE this winter if I had seen any dexos1 Gen 2 jugs at the WMs around here (just peeked last night and still didn't see any, but I did notice some M1 5W30 EP d1G2 jugs for the first time), but one thing I prefer about M1 5W30 by comparison is that you can find all kinds of info about the latter online...a PQIA analysis, a Russian Oil Club analysis, and other VOAs and UOAs. It's very hard to find similar info about the 0W30.

Why use a 5W-30 when you can use a 0W-30?

Originally Posted By: HosteenJorje
Why use a 5W-30 when you can use a 0W-30?
Usually a lower noack. However I'd usually pick either 5w20 or 10w30 in those cases.

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Originally Posted By: Shannow
Originally Posted By: Rolla07
Either will work but I like to think the 0w will be easier on my engine during any cold starts.
see, that's the problem with the laws of physics...they don't really mind what people like to think. at 32F, if anything has a slight edge it will be the marginally thinner 5W30. As to what you've lost Dexos HTO-06 lighter basestocks with more "fillers'
Based on Mobil's web site and Center's for Quality Assurance, Mobil 1 0w30 meets dexos1 Gen2... License number D10102GH015.

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