Synthetic vs Conv...Cold weather

[geeeman]

It has been VERY cold where I live over the past couple of weeks, as low as -30c (-22f). In my frozen stupor, I was wondering if a synthetic say, 10W30 would pump and flow way better than a conventional 10w30, or be very close. I realize that both oils must pass standardized tests to obtain the 10W designation, but does a synthetic "easily" pass vs a dino oil "barely" passing. And...is a synthetic 10W30 very close to a 5W30 dino with regards to flow and pumpability? How about after say, 3000 miles? How about a 15W synthetic like M1 vs a 5W dino like Pennzoil? Once I warm up I'll be OK...really! PS - I have M1 0w40 in one car and GC 0W30 in the other car, both work well in these temps. I have 5W30 in my truck; it isn't quite as good, as is probably to be expected.

 

[HOndaGuy]

Syns are better at cold starts, PERIOD. They are thinner at startup, and a syn 10w30 will flow better than a conv 5w30. Since you are in canada, I would run syn all year round.

 

[Dr. T]

I was going to post the same question today too! Thinking in the shower again... I think it doesn't matter....a 10W is a 10W weather it's synth. or conv.. Synth's have a lower pour point, but who cares? Pour points have nothing to do with cranking numbers...ie. synth's only stay thinner longer before solidifying. For eg., a synth. may have a pour point of -50C wheras the same grade conv. may be -35C, however they will be the same thickness at a certain required temp. eg. -25C. Not sure about a few thou miles down the road though....What happens when the oil thins out? What about when they thicken again. Maybe that's when the synth's shine with respect to better maintaining their original CCS numbers...

 

[Patman]

That's exactly it Dr.T, the synthetics are going to maintain their CCV numbers much better than a conventional oil will. A 5w30 conventional oil would probably only keep it's 5w rating for a short period of time, then it's cold cranking performance would suffer to the point where it would end up being a 10w. I sure am glad we don't get down to -30C here ever. I think today's -8C feels cold enough (especially with these 60km/h winds!) I am so glad I have underground parking here at work, which I've noticed never gets below 54F.

 

[Drew99GT]

A synthetic 10w-30 WILL NOT always pump better than a conventional 5w-30, even if the synthetic has a pour point that's a lot lower than the conventional. Put Mobil 1 10w-30 in a freezer along side your favorite brand of conventional 5w-30 where the temp is at least 0 degrees F. I garuntee you that Mobil 1 10w-30 will seem like Molasses compared to dino 5w-30; I've done this test many times. In fact, I had a spare bottle of Mobil 1 10w-30 that I stuck outside last night where it was 8 below 0, and it was way way thicker and more viscous than 5w-30 pennzoil. However, pennzoil high mileage 5w-30 was on par or slightly thicker than 10w-30 mobil 1. IF the temp was say, -30 degrees F or lower, then the synthetic 10w-30 would outperform the dino, ala it would actually show movement.

 

[TC]

You can find some good, basic information on cold weather oil properties here: http://www.motoroilbible.com/five.html An oil's Borderline Pumping Temperature (ASTM D3829/D4684) is the lowest temperature at which the oil will pump and maintain adequate oil pressure within an engine, and is often anywhere from 5 to 15 or 20 degrees F above the pour point. Most oil firms don't publish their oils' BPTs, but I noticed that Pennzoil does for their conventionals, but for some reason not for their synthetics. PENNZOIL'S BPTs for their conventional gasoline oils are: 5w-20: -35C/-31F 5w-30: -35C/-31F 10w-30: -30C/-22F 10w-40:30 -30C/-22F CITGO publishes BPTs for both their conventionals and synthetics. Note that these are very similar to Pennzoil -- not a typo on my part: 5w-20 Conv: -35C/-31F 5w-30 Conv: -35C/-31F 10w-30 Conv: -30C/-22F 10w-40 Conv: -30C/-22F 5w-30 Syn: -35C/-31F 10w-30 Syn: -30C/-22F Lastly, here's a few PENNZOIL Pour Points: 5w-20 Conv: -45C/-49F 5w-30 Conv: -42C/-44F 10w-30 Conv: -36C/-33F 5w-20 Syn: -42C/-44F 5w-30 Syn: -48C/-54F 10w-30 Syn: -45C/-49F It appears that synthetics have the edge here, as expected, but much less of a difference than I anticipated. But the Pour Point enhancers in conventional are not known for longevity. Believe it or not, somehow our grandfathers managed to get their DeSotos through the snow without replacing the engine every year, and without a drop of synthetic oil in sight. Must have been done through pixies (with beehive hairdos) and fairy dust...

 

[MRC01]

quote:

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Originally posted by TC: Believe it or not, somehow our grandfathers managed to get their DeSotos through the snow without replacing the engine every year, and without a drop of synthetic oil in sight. Must have been done through pixies (with beehive hairdos) and fairy dust...

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Weren't those DeSotos ready for a rebuild at 50,000 miles? We expect 5 times that out of our modern engines.

 

[geeeman]

quote:

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Somehow our grandfathers managed to get their DeSotos through the snow without replacing the engine every year, and without a drop of synthetic oil in sight.

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You've got a point there... Winter comes every year without fail; and cars start every year, ALMOST! without fail, regardless of the oil...!

 

[buster]

quote:

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You've got a point there... Winter comes every year without fail; and cars start every year, ALMOST! without fail, regardless of the oil...!

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Very true. Remember, most of us on here are the .0000000001% of the population that are extremely fanatical and are extreme perfectionists when it comes to motor oil. No one in my family has ever had a engine problem related to oil or couldn't start the car bc the oil wouldnt flow. I think it's good to remind our "sick in the head" selves about these things once in awhile.

 

[TC]

Yeah, a modern engine will last at least twice as long as that DeSoto. But this routinely happens using conventional oil in both warm and cold climates, so this reflects advances in both engine design/manufacturing and API oil ratings. The lesser engine life of the DeSoto would have occurred even in warm Phoenix -- it has nothing to do with frigid oil pumping characteristics. IMO, syn is better (as everyone claims), but a conventional with a -31F pumping rating is certainly sufficient for a majority of snow eaters, so long as it's changed regularly to compensate for pour point degradation.

 

[DockHoliday]

Over the last two winters, I used Mobil 1 10W30 (installed by the Volvo dealer), and this year, I handed them a jug of Amosil 0W30 S2K. With the Mobil 1, the really cold starts were noisy, the engine sounded very tight and as if it was straining. Today, I started the car at 3F, and it started and ran just like any other day. I was very impressed and happy. Not very scientific, but it appears to me that the 0W30 Amsoil kicks but over the Mobil 1 10W30 for cold starts

 

[buster]

quote:

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Amosil 0W30 S2K

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I'd say there are more complaints about Mobil 1 making noise then any other oil out there. There is definitely some truth to this. Amsoil 0w-30 has excellent cold flow ability. I have ASL in now with 4,200 miles on it and cold starts have been nothing for it. I'm waiting this weekend for when it drops down in the lower teens.

 

[greencrew]

The 0W or 5W is measured at 40* C. That's not very cold compared to -30* F. Pour point is everything when the temp is below 0. A typical synthetic will not thicken as fast as a typical dino of the same weight as the temp drops below 0. Here is a quote from the above link. "Synthetic oils, on the other hand, routinely have pour points around -50 degrees F or colder. Some have pour points as low as -60 to -70 degrees F. Granted, there are very few of us who will ever have to start our car at this temperature, but imagine how well these oils lubricate at -20, if it they still flow at -70. And, because synthetics don't need additives to maintain their low temperature fluidity (as we discussed earlier), they continue to flow at these extremely low temperatures for a much longer period of time."

 

[Ken2]

0W oil is measured at -35°C 5W -30 10W -25 15W -20°C See SAE J300 specs http://www.infineum.com/information/viscosity.html The only test at +40°C for engine oil is the lower end of the viscosity index test (100°C is the upper end), as far as I know. Ken

 

[Drew99GT]

quote:

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Originally posted by greencrew: The 0W or 5W is measured at 40* C. That's not very cold compared to -30* F. Pour point is everything when the temp is below 0. A typical synthetic will not thicken as fast as a typical dino of the same weight as the temp drops below 0. Here is a quote from the above link. "Synthetic oils, on the other hand, routinely have pour points around -50 degrees F or colder. Some have pour points as low as -60 to -70 degrees F. Granted, there are very few of us who will ever have to start our car at this temperature, but imagine how well these oils lubricate at -20, if it they still flow at -70. And, because synthetics don't need additives to maintain their low temperature fluidity (as we discussed earlier), they continue to flow at these extremely low temperatures for a much longer period of time."

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Try again. Pour point is basically meaningless when it comes to an oils ability to realistically pump through an oil pump and through tiny tiny passages in an engine, and therefore, cold cranking viscosity is a much more meaningful measure. Mobil 1 15w-50 has a very low pour point, but it's cold cranking viscosity is thick compared to a dino 5w-30 with only a -27 degree pour point (Pennzoil 5w-30 HM). Kinematic viscosity at 40 C is not the same measure or even metric used to determine the 5w or 10w etc. portion of a multi viscosity oil.

 

[Pablo]

Ken2 nailed it. Look at the spec chart and then look at the individual oil's numbers. The xW number for most quality synthetic oils are at the low end for the cranking and pumping vis. numbers. It may be a bit deceiving because the numerical difference is not huge (but they are different, syn vs. dino), I tell you in practical application there is a huge difference. 9°F this AM, 15W-40 synthetic didn't even hesitate.

 

[Hankrr]

quote:

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Originally posted by Drew99GT: A synthetic 10w-30 WILL NOT always pump better than a conventional 5w-30, even if the synthetic has a pour point that's a lot lower than the conventional. Put Mobil 1 10w-30 in a freezer along side your favorite brand of conventional 5w-30 where the temp is at least 0 degrees F. I garuntee you that Mobil 1 10w-30 will seem like Molasses compared to dino 5w-30; I've done this test many times. In fact, I had a spare bottle of Mobil 1 10w-30 that I stuck outside last night where it was 8 below 0, and it was way way thicker and more viscous than 5w-30 pennzoil. However, pennzoil high mileage 5w-30 was on par or slightly thicker than 10w-30 mobil 1. IF the temp was say, -30 degrees F or lower, then the synthetic 10w-30 would outperform the dino, ala it would actually show movement.

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I don't think I believe you are you for sure?? I've been using Mobi1-1 10w30 for years and when I first switched I sure noticed it poured a LOT faster and easier than the dino 10w30 oils I had been using. Granted I have not compared pouring against a 5w30 dino oil but I know for fact in very cold weather 10w30 to 10w30 it pours much much faster. At any rate there is no way in hell Mobil-1 10w30 is anything CLOSE to being like Molasses at 0 degrees as you state above. I've poured it to many times at close to that temp to know otherwise.

 

[Drew99GT]

Someone above stated that 10w-30 Mobil 1 would outperform 5w-30 conventional in cold temps, not 10w-30 conventional. Of course Mobil 1 10w-30 will outflow a conventional 10w-30. And this morning on my deck, where Mobil 1 10w-30 was placed alongside pennz 5w-30 and pennz 5w-30 HM in a snowdrift at -8 degrees F, Mobil 1 10w-30 poured a little easier than Molasses compared to 5w-30 pennzoil, but the Mobil 1 was noticeably thicker. [ January 06, 2004, 10:21 PM: Message edited by: Drew99GT ]

 

[hotrod]

-4F this morning in N. Ill., '03 Tundra V8, 3000 mi., M1 5w30 with 2000 mi., parks outside :-(, cranked a little slower and sounded a little different than day before (20F). Oil pressure rose at seemingly normal rate (visual impression only). Wonder how much of the differences during cranking were due to cold battery as opposed to cold oil?

 

[Drew99GT]

One other thing: Supersyn seems to be thicker when cold compared to Trysynthetic. I do remember putting 10w-30 trysynthetic in my freezer when it first came out, and it was about equal to 5w-30 pennzoil at the time.