Thin oil question

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Hi. Question: Why do people choose a 1ow4o when a ow4o or 5w4o is available? Doesn't the first number coincide with cold pour temp, at zero degrees, and therefore is thinner, therefore flows better and gets in all the nooks and cranies to take away gunk and nasties better than a thicker 1ow oil? I'm particularly refering to the M1 ow4o or GC ow3o vs. my beloved M1 5w4o (tdt). I understand its a diesel oil and all but let's take the ultra-cleaning properties out of the equation please. Educate me. -A
 
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 Originally Posted By: ARMY_Guy
Hi. Question: Why do people choose a 1ow4o when a ow4o or 5w4o is available? Doesn't the first number coincide with cold pour temp, at zero degrees, and therefore is thinner, therefore flows better and gets in all the nooks and cranies to take away gunk and nasties better than a thicker 1ow oil? I'm particularly refering to the M1 ow4o or GC ow3o vs. my beloved M1 5w4o (tdt). I understand its a diesel oil and all but let's take the ultra-cleaning properties out of the equation please. Educate me. -A
0 and 5W40's are synthetics and are typically more expensive than 10W40. I choose 10W40 in my Jeeps during the summer where the pour point is not an issue and because dino is perfectly fine for my application. Also, there are no "Nook's and Crannies" in your engine that thicker oil will not get to just as well as thin oil. Please don't mention this again or I will not be responsible for BuickGN's responses.
 

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Historically, the closer the first number is to the second number, the more "stable" the viscosity of the oil, IE, it is less likely to shear. Most of the HDEO synthetic 5w40 oils are VERY visc-stable, and do not tend to shear much.
 
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Hmm, that's a good question I recently had with the M1 30 weight oils. I'll post the sheet below. What was interesting is that the 10w-30 is thinner than 5w-30 at both room temp and boiling temp. What it would seem, looking at these limited specs, is that going from a generic 15w-40 to a 0w-40 you're trading High Temp High Shear performance for some low temp performance. For example, the 0w has a HTHS of 2.99, 5w is 3.09~3.10, 10w is 3.14~3.66. Now I best go hide, as I'm making assumptions I can never possibly back up.... ........M1 530 M1 1030 suv 530 AFE 030 HM 1030 EP 530 EP 1030 CST 100 11.3... 10..... 11.3... 11..... 11.79.. 11..... 10.7 CST 40. 64.8... 62..... 64.8... 63.1... 78.2... 61..... 66 VIndex. 169.... 147.... 169.... ....... 145.... 169.... 148 FlashP. 230.... 224.... 230.... 228.... 231.... 230.... 230 PourPt. -48.... -45.... -54.... ....... -54.... -48.... -45 Density 0.8.... 0.86... 0.86... 0.845.. 0.865.. 0.86... 0.86 HTHShea 3.09... 3.14... 3.09... 2.99... 3.66... 3.1.... 3.1
 
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10W-40 was 'the' oil to use through the 1970's and early 1980's. Some remember that as a good grade to use. I was working in Wal-Mart once, and a very old lady came up to me, bottle of Pennzoil 10W-40 in hand, and asked, 'IS this the oil I should use in my Buick Century? I'm pretty sure this is what my husband used to put in our Centuries..' I found out it was a 2002 Century, so she needed 5W-30. But I was thinking, yeah, that's what he put in your 1975 Century!!!
 
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No. The "x"W number does not coincide with 0F. It actually is cranking and pumping viscosity measured at different temps. 0W is tested at -35C cranking and -40C pumping 5W is tested at -30C cranking and -35C pumping 10W is tested at -25C cranking and -30C pumping And so on and so forth up to 25W measured at -10C and -15C The actual numbers for these tests remain the same, just the temperature is different. http://www.widman.biz/Seleccion/Viscosidad/SAE_J300/SAE_J300_English/sae_j300_english.html Why would someone use a 10W over a 0W or 5W? Cost. 10W will cost less than a 0 or 5W, depending on grade. A 5W30, 10W30, and 10W40 conventional will cost about the same. However a 0W just about guarantees a synthetic or mostly synthetic stock, which raises the price. If you jump to a 40 grade like in your example a 5W40 is almost always a full synthetic and a 10W40 really should be a blend at least as well, IMO. Strength. Actual shear stability of the oil. The resistance of an oil to fall out of grade. For example M1 0W40 is known to shear back and become a 0W30. Is it a problem? Probably not. But it would be nice if it stayed where it was when one put it into their engine baring some sort of issue. A 5W40 does not have as much of a spread and usually end up being diesel rated oils like TDT, so they are built better in this area. This why I think a 10W40 should be at least a blend, for shear stability. Need. Unless you are living in Canada or above, you probably do not need a 0W. You could probably use M1 HM 10W40 or Valvo Maxlife 10W40 (blend or full) and your engine would be happy.
 
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when ur engine is first started in the morning, it is not at 40 degrees C, it may only be at 5 degrees C, and has the consistency of honey. during the start up phase, that kind of consistency does not flow well and does not lubricate well. even in the desert climate of death valley, it gets COLD at night, and your oil is TOO THICK. a 0wx oil will flow better than a 5wx or a 10wx, but that also depends. for instance a synthetic 10w30 will flow and pump just about the same as a conventional 5w30. you basically do not need anything thinner than a 5w30, but if you are going for an xw40 or xw50, then this oil well be VERY much like honey. I would avoid 10w40 conventional altogether. 5w30 conventional has been recommended by the manufacturer for MANY YEARS now because the engines last MUCH LONGER. Modern 5w20 has been so much improved that it can even be used, but mainly for fleet mileage. personally i might use one part semi-synth 5w20 with 2 parts synth 5w30 in winter. 46$ will buy 15 quarts, which is enough for 3 oil changes, 15$ of oil per change. if it is in the heat of summer, and long summer holiday trips are planned, i will blend 5w30 conventional with 10w30 synthetic, for extra durability. the 10w30 synth has excellent flow properties that match the conv 5w30, and very high shear stability.
 
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 Originally Posted By: Zaedock
 Originally Posted By: ARMY_Guy
Hi. Question: Why do people choose a 1ow4o when a ow4o or 5w4o is available? Doesn't the first number coincide with cold pour temp, at zero degrees, and therefore is thinner, therefore flows better and gets in all the nooks and cranies to take away gunk and nasties better than a thicker 1ow oil? I'm particularly refering to the M1 ow4o or GC ow3o vs. my beloved M1 5w4o (tdt). I understand its a diesel oil and all but let's take the ultra-cleaning properties out of the equation please. Educate me. -A
0 and 5W40's are synthetics and are typically more expensive than 10W40. I choose 10W40 in my Jeeps during the summer where the pour point is not an issue and because dino is perfectly fine for my application. Also, there are no "Nook's and Crannies" in your engine that thicker oil will not get to just as well as thin oil. Please don't mention this again or I will not be responsible for BuickGN's responses.
LOL. Too tired today. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1497570&fpart=1
 
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Put a 0w and a 10w in your freezer (~ -10degF) over nite. The next day, shake both bottles - the 0w will slosh, the 10w won't make a sound. I'm probably being paranoid given that I'm in Arkansas, but I'm not running a 10w over the winter months.
 
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 Originally Posted By: ericthepig
Put a 0w and a 10w in your freezer (~ -10degF) over nite. The next day, shake both bottles - the 0w will slosh, the 10w won't make a sound. I'm probably being paranoid given that I'm in Arkansas, but I'm not running a 10w over the winter months.
I've put my Amsoil ACD straight 30 in the freezer for 48 hours and it still sloshed around just fine. This was way back when I was deciding to run it year round in the TL. The freezer is colder than the car will ever see and it flowed great. Nearly 70,000 miles and two winters later everything is fine. The temp of the freezer is unknown, but it's obviously below freezing.
 
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 Originally Posted By: Onmo'Eegusee
Recommended freezer temp is generally 0F.
Interesting. Mine can't be that cold, the ACD sloshed around way too easily but it would be neat if that turns out to be true. I'll have to buy a thermostat to put in there to know for sure. I also had the ATD and some old M1 5w-30 in there at the same time. I really couldn't see a difference beteen the ACD and M1 but I'm sure the engine would see the difference.
 
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For my scientific slosh test, I always use the upright freezer in the garage - it stays at about -12degF. I'm not sure what the freezer with the frig. runs. I'll put the therm. in there tonite and find out.
 
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10W-40 oil is bad news. Always has been. If it is conventional oil, it has too much viscosity spread (30 points) and that requires too high a proportion of viscosity index improver polymers. These do not lubricate. They make the oil thick when the viscosity is tested hot flowing through an orifice, but the oil does not protect as well as an oil truly this viscosity without the VIIs. When the VIIs shear, you don't even have the illusion of the higher viscosity. Avoid 10W-40. If you feel the need for a 40wt oil, get a 15W-40 or 5W-40. If all your engine needs is a 30wt oil, get any of the many top quality 10W-30 or 5W-30.
 
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During the late 70's and early I reringed many Chevrolet engines that had stuck oil rings due to the viscosity improvers sticking the rings on cars that were driven granny style. The engines would run fine but use oil and upon tear down the engines look clean ets. 10w-30 is by far a better oil.
 
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 Originally Posted By: Zaedock
. . . Also, there are no "Nook's and Crannies" in your engine that thicker oil will not get to just as well as thin oil. Please don't mention this again or I will not be responsible for BuickGN's responses.
But there are bearings with tight clearances, tightly fitted pistons/rings, and so forth. By your reasoning, I suppose everyone up in Minnesota, Wisconsin, and the Dakotas should just go ahead and use SAE-60 racing oil in the dead of winter. Hey, if there are no challenges to oil flow, who needs any thin oils?
 
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 Originally Posted By: ekpolk
But there are bearings with tight clearances, tightly fitted pistons/rings, and so forth.
+1 and in some engines pumps designed specifically for the thinner oils.
 
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Hi, ARMY_Guy - The latest range of 10W-40 semi-synthetic lubricants are proving to be very popular. They may not be available in NA I have used Mobil's Synth "S" 10W-40 in a number of engines over the last several years with excellent results. The latest OZ version of this is called Mobil "2000" 10W-40 and I have just done some OCs using the new product It has excellent cold and hot operating characteristics and will do a great job where specified Porsche in Germany use it as their "service" fill in older engine families. Once they used 15W-40 mineral lubricants in these applications Many people will use this type of lubricant as it is in the right price range - and offers excellent performance Many Oil Companies are now offering these modern semi-synthtic products
 
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